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Medical Laboratory Science Review: Clinical Chemistry 2

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Ideal Sample Tubes
Red top, serum separator for most tests
Heparin (green top)
Specifically for ammonia and blood gases.
Sodium Fluoride (Grey Top)
Glucose (slows glycolysis)
DO NOT USE FOR BUN (inhibits urease)
EDTA (purple top)
Not for Na, K, Ca.
Glucose
End product of carbohydrate digestion in the intestine. Blood glucose is maintained at a fairly constant level by hormones. Insulin lowers. Provides energy for life processes.
Glucose test handling
Refrigerated serum is fairly stable, sodium fluoride (grey top) slows glycolysis.
Glucose fasting reference range
70-99 mg/dL Arterial and capillary values are 2-3 higher. CSF values are two thirds of serum.
Insulin source
beta cells of islets of Langerhens of pancreas
Insulin action
lowers serum glucose. Stimulates glucose uptake by cells.
Glucagon source
alpha cells of pancreas
Glucagon action
Increases glucose, stimulates glycogenolysis (breakdown of glycogen to glucose)
ACTH source
anterior pituitary
ACTH action
Increases glucose, insulin antagonist
Growth Hormone source
Anterior Pituitary
Growth Hormone Action
Increases glucose, insulin antagonist, acromegaly=hyperglycemia
Cortisol source
adrenal cortex
Cortisol Action
increases glucose, stimulates gluconeogenesis (glucose from non-carbohydrate sources)
Human Placental Lactogen source
Placenta
Human Placental Lactogen action
increases glucose, insulin antagonist
Epinephrine source
adrenal medulla
Epinephrine action
Increases glucose, stimulates glycogenolysis, Pheochromocytoma-tumor of adrenal medulla to hyperglycemia.
t3 and t4 source
Thyroid gland
T3 and T4 action
increases glucose, stimulates glycogenolysis
Normal values for fasting plasma glucose
<100 mg/dL
Normal values for Oral Glucose Tolerance Test
2 hr PG <140 mg/dL
Normal Values for A1C
<5.5 %
Diabetes Mellitus values for fasting plasma glucose
>126 mg/dL
Diabetes Mellitus values for casual plasma glucose
>200 mg/dL plus unexpected weightloss, polyuria, polydipsia
Diabetes Mellitus values for oral glucose tolerance
>200 mg/dL
Diabetes Mellitus values for A1C
>6.5%
Pre-diabetes fasting plasma glucose
>100 <126 mg/dL
Pre-diabetes OGTT
2 hr >140<200 mg/dl
Hb A1c
Monitors diabetes. Glucose attaches to hemoglobin. Average glucose level over 90 days. Expresses as %. Diagnosis of diabetes.
Fructosamine
Assess intermediate- term control. Glucose attaches to proteins including albumin. Average glusoce level over 2-3 weeks.
C Peptide (reflects pancreatic secretion of insulin)
Proinsulin cleaved to give C peptide and insulin. Reflects endogenous insulin production if patient is taking insulin.
eAG
Estimated Average Glucose.
eAG formula
eAg = (28.7 X A1c) - 46.7
Glucose testing: Enzymatic
Coupled reactions. Glucose oxidase coverts H2O2 to O2. O2 + chromogenic acceptor gives color (urine dipsticks).
Glucose testing: Hexokinase
Reference method. Glucose + ATP+ Hexokinase = G6P + ADP. G6P +NADP+G6PD=NADPH. NADPH measured directly at 360 nm or coupled to chromogen and measured in visible range.
Lactose Tolerance Test
evaluates defiency of lactase in small bowel. Ingest lactose and measure blood glucose.
Xylose absorption test
Xylose absorbed and ecreted into urine without need of pancreatic enzymes. Helps distinguish intestinal malabsorption and pancreatic-based malabsorption.
Lactic Acid Test
Indicator of oxygen deprivation. End product of glucose metabolism when oxygen deprivation occurs. Build up results in lactic acidosis. Sample collection and handling critical.
Apolipoproteins
Protein potion of lipoproteins. Apolipoprotein A is the major protein of HDL. Apolipoprotein B is the major protein of LDL. Apolipoprotein C is the major protein of VLDL and chylomicrons and minor protein of HDL and LDL.
Triglycerides Function
Primary form of lipid storage
Triglyceride transportation
Chylomicrons (exogenous) VLDL (endogenous)
Cholesterol Function
Important in cellular physiology. Precursor to steroid hormones.
Cholesterol transportation
LDL to cells, HDL out of cells
Lipoprotein Classes
Chylomicrons, VLDL, LDL, HDL
Chylomicrons
Exogenous triglycerides
VLDL
Endogenous triglycerides
LDL
Cholesterol to the cells
HDL
Cholesterol out of the cells
Specimen collection for lipoproteins
12 hour fast required, non fasting may cause turbid serum and high triglycerides.
Cholesterol methods
Enzymatic (cholesterol oxidase)
Triglyceride methods
Enzymatic methods involve liberation of glycerol by lipase.
Falsely elevated triglyceride values caused by...
contamination from stoppers of evacuated tubes or ingestion of glycerol-coated medication
HDL methods
direct or homogenous assays. Measure HDLc without pretreatment. Indirect- remove chylomicrons, VLDL, and LDL by precipitation; analyze supernatant for HDLc.
LDL methods
Direct or homogenous assays. Measure LDLc without pretreatment.
Other lipid methods
Electrophoresis, Ultracentrifugation, Friedwald Method
Cardiac risk factors
Age (>45 men, >55 women), Family history, smoking, hypertension, HDLc <40 mg/dL, diabetes mellitus, metabolic syndrome.
Negative cardiac risk factors
HDLc >60 mg/dL, LDLc <100 mg/dL
Aminoacidurias caused by overflow of plasma above renal threshold
PKU and Branched chain ketoaciduria (maple syrup disease)
Aminoacidurias caused by normal plasma level but decreased renal threshold or reabsorption
Cytinuria (high Cystine), lysine, ornithine, arginine in urine
Amino Acid screening tests
Thin layer chromatography with ninhydrin, urine color tests, Guthrie microbiological tests (PKU)
Amino acid quantitative tests
Ion-exchange chromatography, high performance liquid chromatography, gas chromatography, Gas chromatography mass spectrometry.
Homocysteine (blood)
HIgh levels associated with high risk of cardiovascular disease, stroke, slzheimers, and osteoporosis. High levels if nutritional deficiencies of B6, B12, and folate.
Proteins (general)
Synthesized and catabolized in the liver. Carbon, hydrogen and nitrogen. Amino acid is basic unit.
Protein breakdown products
Urea and ammonia
Kjeldahl method
Serum total protein. Reference method. Measures nitrogen content. Acid digestion converts nitrogen in protein to ammonium ion which is measured. Infrequently used.
Biuret Reaction
Serum total protein. used most frequently. Depends on presence of >2 peptide bonds which bonds to form a purple complex with copper salts in alkaline solution.
Urine and CSF total protein
Coomassie brilliant blue (dye). Turbidimetric methods (acid precipitates protein).
Dye-Binding methods for albumin
bromocresol green. HABA (Hydroxyazoenzene benzoic acid).
Protein electrophoresis migration direction
depends on an electrical field determined by the surface charge of the protein.
Protein electrophoresis at a pH higher than the isoelectric point will travel...
in the direction of the anode (positive charge) and has a negative charge.
Albumin electrophoresis
Smallest MW. Largest number of free negatives and migrates most rapidly
Urine protein electrophoresis
same as serum except it must be concentrated before application
Electroendosmosis
causes gamma globulins to migrate toward the cathode even though they are slightly negatively charged (because of the electrical charge on support medium).
at pH 8.6, migration order is
Albumin, alpha-1, alpha-2, beta, and gamma
Support media for electrophoresis is...
cellulose acetate, agarose gel, and starch gel
Stains for electrophoresis include...
Amido black, Ponceau S and coomassie brilliant blue
Specimen collection for electrophoresis
Plasma- Result in fibrinogen peak migrating between gamma and beta.
Recollect and verify that it is in fact fibrinogen.
Clinical significance of electrophoresis
Liver produces albumin, alpha1, alpha2, and beta globulins. RE system produces gamma globulins (secreted by plasma cells). Prealbumin is a faint band. Used to assess nutrition.
Albumin (percent of plasma)
52-62%
Albumin function
regulator of osmotic pressure, transport protein.
Causes of low albumin
Liver impairment, edema, malabsorption, malnutrition, nephrotic syndrome, severe burns
Alpha 1 antitrypsin values
High in acute phase or pregnancy, low associated with emphysema in neonates
Alpha fetoprotein
High in amniotic fluid and maternal serum in neural tube defects, liver cancer marker, low in maternal serum during pregnancy associated with Down's Syndrome
Aplpha-2-globulins
Haptoglobin binds to free hemoglobin. High in acute phase and nephrotic syndrome, low seen in transfusion reactions, low in hemolysis and liver disease. Ceruloplastin transports copper and is high in acute phase and pregnancy, low in Wilson's disease.
Beta globulin
Carrier proteins for iron (transferrin) and lipids (lipoproteins). High in elevated beta lipoproteins and iron deficiency anemia
Gamma globulin
HIgh in chronic inflammation, cirrhosis or viral hepatitis, collagen diseases, and paraproteins. Low in congenital or acquired immune-deficiency
Beta Gamma Bridge (electrophoresis)
One hump between beta and gamma areas, active cirrosis
Monoclonal gammopathy (electrophoresis)
High gamma peak
Nephrotic syndrome (electrophoresis)
High Alpha 2
Hypogammaglobulinemia
No gamma peak
Enzymes
Catalysts
Enzyme reaction measurements affected by
Concentration of reactants, pH, temperature, Ionic strength, cofactors and coenzymes
Competition inhibitor (enzyme)
binds free enzyme at the active site
Noncompetitive inhibitor (enzyme)
binds at a site other than the active site
Uncompetitive inhibitor (enzyme)
binds only to the enzyme substrate complex
Enzyme measurement Zero order kinetics
Large excess of substrate so that the amount of enzyme activity is only rate-limiting factor
Enzyme measurement catalytic activity rate
directly measured
Total CK (creatine kinase)
High in muscle, cardiac, or brain damage.
CK isoenzymes
CK-BB (two B chains), CK-MB (1 m and 1 B chain), CK-MM (2 M chains)
Cardiac muscle (CK)
CK-MM and CK-MB
Skeletal Muscle (CK)
CK-MM
Brain, GI, Colon, prostate, uterus
CK-BB
Lactate dehaydrogenase
Elevated in myocardial infarction, liver disease, muscle trauma, renal infarct, hemolytic diseases, pernicious anemia
sources of error with LD
hemolyzed specimens, prolonged contact of serum to cells
Spectrophotometric method (LD)
LD converts pyruvate to lactate while oxidizing NADH to NAD.. Rate of decrease in absorbance of NADH at 340 nm is proportional to LD activity
LD isoenzymes
2 chains (M and H). 4 subunits, 5 forms (tissue specific)
Aspartate Transaminase (AST)
Found in cardiac muscle, liver, RBC, and other tissues.
Elevated AST
In myocardial infarction, liver disease, muscle trauma, renal infarct, and hemolysis.
Alanine transaminase (ALT)
More liver specific than AST
Elevated ALT
high in liver disease
Gamma-glutamyl transferase (GGT)
High in liver disease, high after alcohol intake, spectrophotometric method measures nitroaniline released when GGT acts of substrate gamma-glutamyl-p-nitroanilide
Alkaline phosphatase (ALP) optimum pH
pH 10; Mg2+ activation
ALP source
found in bone, intestinal mucosa, renal tubule cells, biliary tree ( liver), leukocytes, placenta, and some tumors.
ALP methods
Isoenzyme separation: acrylamide gel, electrophoresis. Highest concentration in liver.
High ALP
bone disorders with osteoblastic activity. Disorders of hepatic biliary tree, growing children, third trimester of pregnancy.
ALP Spectrophotometric methods
ALP converts p-nitrophenyl phosphate to phosphate and P-nitrophenylate which is measured at 404-410 nm. Immunoassy for bone isoenzyme.
5'NT (5'-Nucleotidase)
High in liver but not in bone disease, high ALP + normal 5'NT = bone disease. High ALP + High 5'NT = liver disease
Amylase
Produced in salivary and pancreatic glands
Amylase requirements
Requires Ca2+ and Cl- (dilute with saline not water)
High amylase
Highest seen in pancreatitis and obstruction to pancreatic ducts
Low amylase
Seen in obstruction of the salivary glands (mumps)
Amylase methods
Amyloclastic- measure disappearance of starch substrate.
Saccharogenic- measure reducing sugars produced by enzymatic reaction.
Chromolytic (dye)- measure absorbance of soluble dye split from insoluble amylase dye substrate.
Urinary amylase elevated
Remains higher than serum for longer.
Amylase false pos
opiates
Lipase
High in pancreatitis, remains elevated longer than amylase, more specific for acute pancreatitis.
Lipase methods
Turbidimetric, olive oil substrate
ACP (acid phosphatase)
Sources: Prostate (primary), erythrocytes, bone, liver, spleen, kidney, platelets.
Clinical significance of acid phosphatase (ACP)
Highest in metastasizing carcinoma of prostate (PSA used instead). High in bone disease or cancers that metastasize to bone and in metastasizing breast cancer. Presence in seminal fluid useful in forensic medicine (PSA used instead).
Acid phosphatase (ACP) methods
Spectrophotometric for total ACP- Phosphate substrate.
Spectrophotometric for Prostatic ACP- Uses substrates more specific for prostate.
Specimen handling for ACP
hemolysis results in false pos. Stored at RT results in loss of enzyme activity; must remove serum from cells ASAP and stabilize.
Cholinesterase
erythrocyte acetylcholinesterase and plasma pseudocholinesterase. Destroys acetylcholine after nerve impulse transmission. Severe low results in serious neuromuscular effects. Low cholinesterase means they may be susceptible to certain anesthetic agents.
Myoglobin
Produced by the muscles. High in muscle and renal damage. Rises within 30 minutes of AMI. Absence rules out AMI, but does not diagnose AMI
CK2 (CK-MB)
Immunoassys: Mass CK2 assays measure concentration rather than activity. Rises within 6-10 hours of AMI, peaks within 24 hours and return's to normal in 2-3 days.
Troponin
is a complex of three proteins in muscle fibers: troponin T, troponin I, and troponin C. Isoforms cTnT and cTnI are very specific to cardiac muscle and either may be used for detection of AMI. Rises 4-8 hours after AMI.
Congestive heart failure
B-Type Natriuretic Peptide (BNP) is active and N-Terminal pro-BNP is inactive. Levels are high in congestive heart failure
BNP
Released by ventricular walls in response to hypertension.
hsCRP
Sensitive marker for chronic inflammation. Patient must be free of other inflammatory processes. Elevated levels potential risk factor.
Homocysteine
Amino acid associated with vitamin B6, B12 and folic acid. Elevated levels potential risk factor.
Liver markers
AST, ALT, LD, ALP, 5' NT, GGT
AST
Highest values in hepatitis
ALT
highest values in hepatitis, liver specific
LD
found in many tissues other than liver
ALP
Biliary obstruction; may be slightly elevated in hepatitis
5' NT
Biliary obstruction
GGT
Liver specific, highest from biliary obstruction or after alcohol ingestion.
Muscule disorders lab values
High CK, AST, aldolase
Acute pancreatitis lab values
High amylase and lipase
Sodium
Major cation of extracellular fluid, 85% is reabsorbed in the kidney tubules, 135-145 mM/L.
Hyponatremia
Low sodium, Diabetic acidosis, diarrhea, Addison's disease, renal tubular disease.
Hypernatremia
Cushing's Syndrome, Dehydration, Hyperaldosteronism, Insulin treatment of uncontrolled diabetes.
Sodium assay methods
Ion-selective electrode. Glass electrode selective for NA+, direct reading. Pseudohyponatremia if high triglycerides.
Potassium
Major cation of intracellular fluid, 3.5-5.0 mM/L, 23 times higher in cells than in plasma
Potassium specimen handling
Separate serum from cells quickly to prevent K+ from shifting to serum. False High if there is hemolysis, EDTA, prolonged tourniquet, >500,000 WBC, >700,000 Platelet.
Potassium serum vs plasma values
Plasma is 0.1- 0.7 lower than serum
K+ high and low values causing...
Heart arrhythmias and or neuromuscular symptoms including weakness and paralysis
Hypokalemia
Insulin injections, Alkalosis, GI losses (diarrhea, vomiting), hyperaldosteronism (low renal absorption), Cushing's Syndrome
Hyperkalemia
Diabetic acidosis, intravascular hemolysis, severe burns, renal failure, Addison's Disease
K+ methods
Ion-selective electrode. Valinomycin membrane selectively bind K+
Chloride
Major anion of extracellular fluid, Maintains hydration, osmotic pressure and the normal anion-cation balance. RR 98-106 mM/L
Hypochloremia
Diabetic acidosis, chronic pyelonephritis, prolonged vomiting (loss of HCl), aldosterone deficiency.
Hyperchloremia
Prolonged diarrhea (excess bicarbonate loss), Renal tubular acidosis, adrenocortical hyperfunction.
Cl- methods
Ion-selective electrodes, coulometric titration, Colorimetry using Hg(SCN)2
Sweat chloride
High in cystic fibrosis, sweat collected by iontophoresis ursing drug, pilocarpine, to induce sweating, >60 mM/L cystic fibrosis.
Chloride shift
Buffering system of the blood, HCO3- pulled out of erythrocytes and CL- moves into erythrocytes resulting in low serum Cl-
Total Carbon dioxide
Reflects bicarbonate concentration.
Total Carbon dioxide methods
Volumetric, manometric, coormetric, pCO2 electrode measures change in internal pH due to CO2.
Anion Gap
Calculation that reflects differences between unmeasured cations and anions; used as analytical QC for measuring all electrolytes.
High anion gap
High concentration of ethanol, ketones, lactic acid. Low serum Mg++ or Ca++
Low anion gap
Low unmeasured anions- albumin loss. High serum Mg++, CA++, lithium therapy. Hemodilution.
Osmolality
Measure of total concentration of dissolved particles in solution. Can be measured directly. Freezing point depression and vapor pressure depression. Accesses unmeasured cations.
Calculated osmol
2Na + Gluc + BUN/2.8
Magnesium
Ca++ channel blocking agent. affects heart. High in renal failure, low in cardiac disorders, diabetes mellitus, diuretics, alcohol or other drugs
Magnesium methods
Atomic absorption, colormetric method (Calmagite)
Calcium
Combines with phosphate in bone, controlled by three hormones (PTH, Calcitonin, Vit D)
Hypercalcemia
High Ca++, Muscle weakness, disorientation
Hypercalcemia happens with...
Hyperparathyroidism, Cancer with bone metastasis, multiple myeloma, renal failure
Hypocalcemia
Hypothyroidism, low serum albumin, low vit D
Calcium methods
Atomic absorption spectroscopy (reference)
Colormetric (most common)- Ca reacts with cresolphthalein to form reddish complex.
ISE
Measures ionized CA2+, pH dependent, collection anaerobically to prevent CO2 loss (high pH). Falsely low if using EDTA or oxalate
Phosphorous
Majority of phosphate in the body is expressed as phosphorous. Measure PO4 only. Inverse relationship with Ca2+
High PO4
Hypoparathyroidism
chronic renal failure
excess vit D
Low PO4
Hyperparathyroidism
impaired renal absorption
PO4 methods
Spectrophotometric methods use molybdate to combine with PO4 ions
Molybdenum blue is formed by the reduction of phosphomolybdate
vitamin D
Functions like a prohormone
Exists in two forms: D2 (dietary form) and D3 (Produced by skin)
metabolized to 1,25 in the liver and then the kidneys
increases blood calcium and phosphorous by increasing dietarty absorption.
Vit D deficiency
Rickets
Osteopenia and Osteoporosis
Hypertension
obesity
diabetes
cardiovascular disease
cancer
autism
Vit D methods
Immunoassay
liquid chromotography
Parathyroid Hormone (PTH)
Synthesis by parathyroid glands stimulated by low Ca, suppressed by high Ca.
What formulas correctly describes the relationship between absorbance and %T?
A = 2-log %T
A = log 1/T
A = -log T
A solution that has a transmittance of 1.0 would have an absorbance of..
2.0
In absorption spectrophotometry...
Absorbance is directly proportional to transmittance
Which wavelength would be absorbed strongly by a red-colored solution?
450 nm
A green colored solution would show highest transmittance at...
525 nm
A tech is performing an enzyme assay at 340 nm using a visible-range spectrophotometer. After setting the wavelength and sdjusting the readout to zero %T with the light path blocked, a cuvette with deionized whater is inserted. With the light path fully open and the 100% T control at maximum, the instrument readout will not rise about 90%T. What is the most appropriate first course of action?
Replace the source lamp
Which type of monochromater produces the purest monochromatic light in the UV range?
A prism and variable exit slit
Which monochromator specification is required in order to measure the true absorbance of a compound having a natural absorption bandwidth of 30 nm?
5-nm bandpass
Which photodetector is most sensitive to low levels of light?
Photomultiplier tube
Which condition is a common cause of stray light?
Dispersion from second-order spectra
What is the most common cause of loss of linearity at high-analyte concentrations?
Stray light
Which type of filteris best for measuring stray light?
Sharp cutoff
Which of the following materials is best suited for verifying the wavelength calibration of a spectrophotometer?
Holmium oxide glass
Why do many optical systems in chemistry analyzers utilize a reference light path?
To minimize error caused by source lamp fluctuation
Which component is required in a spectrophotometer in order to produce a spectral absorbance curve?
Photodiode array
The half-band width of a monochromator is defined by
the range of the wavelengths passed at 50% transmittance
The reagent blank corrects for absorbance caused by
the color of reagents
A plasma sample is hemolyzed and turbid. What is required to perform a sample blank in order to correct the measurement for the intrinsic absorbance of the sample when performing a spectrophotometric assay?
Substitute saline for the reagent
Which instrument requires a highly regulared DC power supply?
A spectrophotometer with a photomultiplier tube
Which statement regarding reflectometry is true?
100% reflectance is set with an opaque film called a white reference
Bichromatic measurement of absorbance can correct for interfering substances if
The concentration of the interferent to absorbance is the same at both wavelengths
Which instrument requires a primary and secondary monochromator?
Fluorometer
Which of the following statements about fluorometry is accurate?
Unsaturated cyclic molecules are often fluorescent
Which of the following components is not needed in a chemiluminescent immunoassay analyzer?
Source lamp
Which substance is used to generate the light signal in electochemiluminescence?
Ruthenium
Light scattering when the wavelength is greater than 10 times the particle diameter is described by
Rayleigh's law
Which statement regarding nephelometry is true?
The detector response is directly proportional to concentration
The purpose of the nebulizer in an atomic absorption spectrophotometer that uses a flame is to
convert ions to atoms
A flameless atomic absorption spectrophotometer dhydrates and atomizes a sample using
A graphite capillary furnace
When measuring lead in whole blood using atomic absorption spectrophotometry, what reagent is required to obtain the needed sensitivity and precision?
triton-X-100
Interference in atomic absorption spectrophotometery caused by differences in viscosity is called
Matrix effect
All of the following are required when measuring magnesium by atomic absorption spectrophotometry except
A 285 nm reference beam to correct for background absorption
When measuring calcium by atomic absorption spectrophotometry, which is required
Lanthanum oxide to chelate phosphates
Ion selective analyzers using undiluted samples have what advantage over analyzers that use a diluted sample
Are not subject to pseudohyponatremia caused by high lipids
Select the equation describing the potential that develops at the surface of an ion-selective electrode is determined by the
Concentration of the potassium chloride filling solution
The term RT/nF in the Nernst equation defines the Slope of the electrode
Concentration of the potassium chloride filling solution
The ion-selective membrane used tho measure potassium is made of
Valinomycin gel
The response of a sodium electrode to a to-fold increase in sodium concentration should be
An increase in potential of approximately 60 mV
Which of the electrodes below is a current-producing producing rather than a voltage-producing electrode?
Clark electrode
Which of the following would cause a response error from an ion-selective electrode for sodium when measuring serum but not the calibrator?
Protein coating the ion-selective membrane
In polargraphy, the voltage needed to cause depolarization of the cathode is called the
Decomposition potential
Persistent noise from an ion-selective electrode is most often caused by
Blocked junction at the salt bridge
Which element is reduced at the cathode of a Clark polarographic electrode?
Oxygen
Which of the following statements accurately characterizes the coulometric titration of chloride?
Constant current must be present across the generator electrodes
In the coulometric chloride titration
the endpoint is detected by amperometry
Which of the following compounds can interfere with the coulometric chloride assay?
Bromide
All of the following compounds contribute to the osmolality of plasma except
Lipids
One mole per kilogram H2O of any solute will cause all of the following except
Raise vapor pressure by 0.3 mm Hg
What component of freezing point osmometer measures the sample temperature?
Thermistor
What type of measuring circuit is used in freezing point osmometer?
Wheatstone bridge
Which measurement principle is employed in a vapor pressure osmometer?
Seebeck
The freezing point osmometer differs from the vapor pressure osmometer in that only the freezing point osmometer
is sensitive to ethanol
The method for measuring iron or lead by plating the metal and then oxidizing it is called
Anodic stripping voltometrey
The term isocratic is used in high performance liquid chromatography to mean the
Mobile phase consists of a constant solvent composition
The term reverse phase is used in HPLC to indicate the mobile phase is
More polar than the stationary phase
What is the primary means of solute separation in HPLC using C18 columns
Partitioning
the most commonly used detector for clinical gas-liquid chromatography is based upon
Flame ionization
What type o detector is used in high performance liquid chromatography with electrochemical detection
Glassy carbon electrode
In gas chromatography, the elution order of volatiles is usually based upon the
Boiling point
Select the chemical that is used in the most HPLC procedures to decrease solvent polarity
Acetonitrile
In thin-layer chromatography, the distance the solute migrates divided by the distance the solvent migrates in the
Rf
Which reagent is used in thin layer chromatography to extract cocaine metabolites from urine
Alkali and organic solvent
What is the purpose of an internal standard in HPLC and GC methods>
To compensate for variation in extraction and injection
What is the confirmatory method for measuring drugs of abuse?
Gas chromatography with mass spectroscopy (GS-MS)
The fragments typically produced and analyzed in methods employing mass spectroscopy are typically
Cations caused by electron loss or proton attachment
What component is used in a GC-MS but not used in an LC-MS
Electron source
What process is most often used in LC-MS to introduce the sample into the mass filter
Electrospray ionization
In mass spectroscopy the term base peak typically refers t
The peak with the most abundance
Which method is the most useful when screening for errors of amino and organic acid metabolism?
Electrospray ionization tandem-mass spectroscopy
In Tandem-mass spectroscopy, the first mass filter performs the same function as
The chromatography solumn
Why is vacuum necessary in the mass filter of a mass spectrometer?
It prevents collision between fragments
What method is used to introduce the sample into a mass spectrometer for analysis of a trace element?
Inductively charged plasma ionization
Which component is needed for a thermal cycler to amplify DNA?
Programmable heating and cooling unit
In real-time PCR, what value is needed in order to determine the threshold
Background signal
In addition to velocity, what variable is also needed to calculate the relative centrifugal force of a centrifuge
head radius
Which of the situations is likely to cause an error when weighing with an electronic analytical balance
Failure to close the doors of the balance before reading the weight
What is the reference range for arterial blood pH?
7.35- 7.45
Which of the following contributes the most to ther serum total CO2?
HCO3-
In addition to sodium bicarbonate, what other substance contributes most to the amount of base in the blood
Hemoglobin concentration
Which of the following effects results from exposure of a normal arterial blood sample to room air>
PO2 increased, PCO2 decreased, pH increased
The normal difference between alveolar and arterial PO@ is
10 mmHg
A decreased PAO-PAO2 difference is found in
Ventilation defects
the determination of the oxygen saturation of hemoglobin is best accomplished by
Polychromatic absorbance measurements of a whole blood hemolysate
Correction of pH for a patient with a body temperature of 38 would require
Subtraction of 0.015
Select the anticoagulant of choices for blood gas studies
lithium heparin
What is the maximum recommended storage time and temperature for an arterial blood gas sample drawn in a plastic syringe?
30 min, 22 degrees
Which set of results is consistent with uncompensated respiratory alkalosis?
pH 7.66, HCO3 22 mmol/L, PCO2 20 mmHG
Which of the following will shift the O2 dissociation curve to the left
ALkalosis
In which circumstance will the reporting of calculated oxygen saturation of hemoglobin based on PO2, PCO2, pH, temperature, and hemoglobin be in error?
Carbon Monoxide poisoning
Which would be consistent with partially compensated respiratory acidosis?
pH decreased, PCO2 increased, Bicarbonate increased
Which condition results in metabolic acidosis with severe hypokalemia and chronic alkaline urine?
Renal tubular acidosis
Which of the following mechanisms is responsible for metabolic acidosis?
Bicarbonate deficiency
Which of the following disorders is associated with lactate acidosis?
Alcoholism
Which of the following is the primary mechanism of compensation for metabolic acidosis
Hyperventilation
The following conditions are all causes of alkalosis. Which condition is associated with respiratory (rather than metabolic) alkalosis?
Anxiety
Which of the following conditions is associated with both metabolic and respiratory alkalosis?
Hypokalemia
In uncompensated metabolic acidosis, which of the following will be normal?
PCO2
Which of the following conditions is classified as normochloremic acidosis?
Diabetic ketoacidosis
Which PCO2 value would be seen in maximally compensated metabolic acidosis?
15 mm Hg
What are the three levels for quality control of pH and blood gases?
Systematic errors can be detected earlier than with two controls
A single point claibration is performed between each blood gas sample in order to
Correct electrode and instrument drift
In which condition would hypochloremia be expected?
Metabolic alkalosis
Which of the following conditions will cause an increased anion gap?
Renal failure
Alcoholism, liver failure, and hypoxia induce acidosis by causing
Depletion of cellular NAD+
Which of the following is the primary mechanism causing respiratory alkalosis?
Hyperventilation
Which condition can result in acidosis?
Excessive O2 therapy
Which of the following conditions is associated with an increase in ionized calcium in the blood
Malignancy
Which of the following laboratory results is consisent with primary hypoparathyroidism?
Low calcium, high inorganic phosphorus Pi
Which of the following conditions is associated with hypophosphatemia
rickets
Which of the following tests is consistently abnormal in osteoporosis?
High urine or serum N-telopeptide of type 1 collagen
Which of the following is a marker for bone formation?
Osteoclacin
What role do CTx and NTx play in the management of osteoporoisis?
Decreased urinary excretion indicates a positive response to treatment
What role does vitamin D measurement play in the management of osteoporosis?
Vitamin D deficiency is a risk factor for developing osteoporosis
Which statement best describes testing recommendations for vitamin D
Testing should be for total Vit D when screening for deficiency
The serum level of which of the following laboratory tests is decreased in both VDDR and VDRR?
Pi
Which of the following is the most accurate measurement of Pi in serum?
Rate of unreduced phosphomolybdate formation at 340 nm
What is the percentage of serum calcium that is ionized
45%
Which of the following conditions will cause erroneous CAi results? Assume that the samples are collected and stored
anaerobically, kept at 4 degrees until measurement, and stored measurement, and stored for no longer than 1 hour
Assay of whole blood collected in sodium oxalate
Which of the following conditions is associated with low serum magnesium
pancreatitis
When measuring calcium with the complexometric dye o-cresolphthalein complexone, magnesium is kept from interfering by
Adding 8-hydroxyquinoline
Which electrolyte measurement is least affected by hemolysis?
Calcium
Which of the following conditions is associated with hypokalemia
Alkalosis
Which of the following conditions is most likely to produce an elevated plasma potassium?
digitalis overdose
Which of the following values is the threshold critical value for low plasma potassium
2.5 mmol/L
Which electrolyte is least likely to be elevated in renal failure?
Sodium
which of the following is the primary mechanism for vasopressin (ADH) release?
Hyperosmolar plasma
Which of the following conditions is assocaited with hypernatremia?
Diabetes insipidus
Which of the following values the threshold critical value for high plasma sodium
160 mmol/L
Which of the following conditions is associated with total body sodium excess?
renal failure
Which of the following conditions is associated with hyponatremia?
Diuretic therapy
Which of the following conditions involving electrolytes is described correctly
Hypoalbuminemia cuases low total calcium but does not affect Cai
Which of the following laboratory results is usually associated with cystic fibrosis?
Sweat chloride greater than 60mmol/L
When performing a sweat chloride collection, which of the following steps will result in analytical error?
Leaving the preweighed gauze on the inside of the arm exposed to the air during collection
Which electrolyte level best correlates with plasma osmolality?
Sodium
Which formula is most accurate in predicting plasma osmolality
2 Na + (Glucose/18) +(BUN/2.8)
Which of the following biochemical processes is promoted by insulin
Uptake of glucose by cells
Which of the following hormones promotes hyperglycemia
Growth hormone
Which of the following is characteristic of type I diabetes
Requires insulin replacement to prevent ketosis
Which of the following is characteristic of type 2 diabetes mellitus?
Hyperglycemia is often controlled without insulin replacement
Which of the following results falls within the diagnostic criteria for diabetes mellitus?
Random plasma glucose of 250 mg/dL and presence of symptoms
Select the most appropriate adult reference range for fasting blood glucose
65-99 mg/dL
When preparing a patient for an oral glucose tolerance test, which of the following conditions will lead to erroneous results
Carbohydrate intake is restricted to below 150 g/day for 3 days prior to test
Which of the following 2-hour glucose challenge results would be classified as impaired glucose tolerance
150 mg/dL
Which statement regarding gestational diabetes mellitus is correct
Is defined as glucose intolerance originating during pregnancy
Which of the following findings is characteristic of all forms of clinical hypoglycemia?
Neuroglycopenic symptoms at the time of low blood sugar
Which statement regarding glycated Hgb is true?
Reflects the extent of glucose regulation in the 8-12 weeks prior to sampling
What is the ADA recommended cutoff value for adequate control of blood glucose in diabetics as measured by glycated hemoglobin?
6.5%
Which statement regarding measurement of HGB A1c is true
Levels do not need to be done fasting
Which stationary phase is used for the measurement of HGB A1c by high performance liquid chromotography?
Cation exchanger
According to the ADA, which result is consistent with a diagnosis of impaired fasting glucose?
117
What is the recommended cutoff for the early detection of chronic kidney disease in diabetics using the test for microalbuminuria?
>30 mg/g creatinine
In addition to measuring blood glucose, HGB A1c, and microalbumin, which test should be done on diabetic persons once per year?
Estimated glomerular filtration rate
Which testing situation is appropriate for the use of point-of-care whole blood glucose methods?
Monitoring of blood glucose control in type 1 and type 2 diabetics
Which of the following is the reference method for measuring serum glucose
Hexokinase
Polarographic methods for glucose analysis are based upon which principle of measurement
The rate of o2 depletion
In addition to polarography, what other electrochemical method can be used to measure glucose in plasma
Amperometry
Select the enzyme that is most specific for beta-D-glucose
Glucose oxidase
Select the coupling enzyme used in the hexokinase method for glucose
Glucose-6-phosphate dehydrogenase
Which glucose method is subject to falsely low results caused by ascorbate?
Trinder glucose oxidase
Which of the following is a potential source of error in the hexokinase method?
Hemolysis
Which statement about glucose in CSF is correct?
Levels below 40 occur in septic meningitis, cancer, and multiple sclerosis
In peroxidase-coupled glucose methods, which reagent complexes with the chromagen?
Phenol
Point of care tests for whole blood glucose monitoring are based mainly on the use of
Amperometric detection
What effect does hematocrit on POCT tests for whole blood glucose monitoring?
Low hematocrit raises readings and high hematocrit lowers readings unless corrected
Which of the following is classified as a mucopolysaccharide storage disease
Hurlers syndrome
Identify the enzyme deficiency responsible for type 1 glycogen storage disease
Glucose-6-phosphatase
Which of the following abnormal laboratory results is found in von Gierkes disease?
Hyperlipidemia
the D-xylose absorption test is used for the differential diagnosis of which two diseases
Pancreatic insufficiency from malabsorption
What is true about carbohydrate intolerance?
galactosemia results from deficiency of galactose-1-phosphate
Which of the following statements regarding iron metabolism is correct?
The daily requirement is higher for pregnant and menstruating women
Which of the following processes occurs when iron is in the oxidized (Fe3+) state?
Binding to transferring and incorporation into ferritin
what is associated with low serum iron and high total iron-binding capacity
Iron deficiency anemia
Which condition is associated with the lowest percent saturation of transferrin?
Iron deficiency anemia
Which condition is most often associated with a high serum iron level?
noniron deficiency anemia
Which of the following is likely to occur first in iron deficiency anemia
decreased serum ferritin
Which formula provides the best estimate of serum TIBC
Serum transferrin in mg/dL X 1.43 = TIBC
Which statement regarding the diagnosis of iron deficiency is correct?
A low serum ferritin is diagnositc
Which statement about iron methods is ture
Colorimetric methods measure binding of Fe2+ to a ligand such as ferrozine
Which of the following statements regarding TIBC assay is correct?
All TIBC methods require addition of excess iron to saturate transferrin
Which of the following statements regarding the metabolism of bilirubin is true
It is produced from the destruction of rbcs
Bilirubin is transported from reticuloendothelial cells to the liver by
Albumin
Bilirubin is transported from reticuloendothelial cells to the liver by
...
Which enzyme is responsible for the conjugation of bilirubin
UDP-glucuronyl transferase
The term S-bilirubin refers to
Bilirubin tightly bound to albumin
Which of the following processes is part of the normal metabolism of bilirubin
Methene bridges of bilirubin are reduced by intestinal bacteria forming urobilinogens
Which of the following is a characteristic of conjugated bilirubin
It is water soluble
Which of the following statements regarding urobilinogen is true
It is formed in the intestings by bacterial reduction of bilirubin
Which statement regarding bilirubin metabolism is true?
Bilirubin undergoes rapid photo-oxidation when exposed to daylight
Which condition is cause by deficient secretion of bilirubin into the bile canaliculi?
Dubin-johnson syndrome
In hepatitis, the rise in serum conjugated bilirubin can be caused by
Failure of the enterohepatic circulation
Which of the following is a characteristic of obstructive jaundice
The ratio of direct to total bilirubin is greater than 1:2
Which of the following would cause an increase in only the unconjugated bilirubin
Hemolytic anemia
Which form of hyperbilirubinemia is causedby an inherited absence of UFP-glucuronyl transferase?
Criler-Najjar syndrome
Which statement regarding total and direct bilirubin is true
Total bilirubin level is a less sensitive and specific marker of liver disease than the direct level
Which statement best characterizes serum bilirubin levels in the first week following delivery
Jaundice is usually first seen 48-72 hours postpartum in neonatal hyperbilirubinemia
Which form of jaundice occurs within days of delivery and usually lasts 1-3 weeks but is not due to normal neonatal hyperbilirubinemia or HDN
Lucey-Driscoll syndrome
Which reagent is used in the Jendrassik-Grof method to solubilize unconjugated bilirubin?
Caffeine
Which statement regarding the measurement of bilirubin by the Jendrassik-Grof method is correct
Fehling's reagent is added after the diazo reaction to reduce optical interference by hemoglobin
In the enzymatic assay of bilirubin how is measurement of both total and direct bilirubin accomplished
usin different pH for total and direct assay
Which is the principle of the transcutaneous bilirubin assay
Multiwavelength reflectance photometry
Which of the following conditions is most likely to cause a falsely high creatinine clearance result
The patient empties his or her bladder at the start of the test and adds the urine to the collection
What substance may be measured as an alternative to creatinine for evaluationg GFR?
Cystatin C
Which of the enzymes allows creatinine to be measured by coupling the creatinine amidohydrolase reaction to the peroxidase reaction
Sarcosine oxidase
Select the primary reagent used in the Jaffe method for creatinine
Saturated picric acid and NaOH
Interference from other reducing substances can be partially eliminated from other reducing substances can be partially eliminated in the jaffe reaction by
measuring the timed rate of the product formation
Which of the following is true
Cystatin C is measured immunochemically
Which analyte should be reported as a ration using creatinine concentrations a reference
urinary microalbumin
Urea concentration is calculated from the BUN by multiplying by a factor of
2.14
A patients BUN is 60 mg/dL and serum creatinine is 3.0 mg/dL. these results suggest
Prerenal failure
Urinary urea measurements may be used for calculation of
Nitrogen balance
BUN is determined electrochemically by coupling the urease reaction to measurment of
the timed rate of increase in conductivity
In the ultraviolet enzymatic method for BUN, the urease reaction is coupled to a second enzymatic reaction using
Glutamate dehydrogenase
Which product is measured in the coupling step of the urease UV method for BUN
NAD+
Which of the following conditions is classified as a renal type aminoaciduria
Fanconi syndrome
What other aminoaciduria can be detected by tandem MS
Citrullinemia
Of the methods used to measure amino acids which is capable of measuring fatty acids simultaneously
Tandem mass spectroscopy
enzymatic measurement of ammonia requires which of the following substrates and coenzymes
alpha ketoglutarate and NADH
which statement about ammonia is true
hepatic coma can result from reyes syndrome
uric acid is derived from the
catabolism of purines
which of the following conditions is associated with hyperuricemia
renal failure
Which uric acid method is associated with negative bias caused by reducing agents
uricase coupled to the trinder reaction
Which statement best characterizes serum bilirubin levels in the first week following delivery
Jaundice is usually first
In the liver, bilirubin is conjugated by addition of
Glucuronyl groups
In the liver, bilirubin is conjugated by addition of
Glucuronyl groups
Which enzyme is responsible for the conjugation of bilirubin
UDP-glucuronyl
Reverse osmosis (RO) is describes as a process:
In which water is forced through a semipermeable membrane that acts as molecular filter.
Activated carbon filters remove:
Organic Compounds from water
A 0.22 micron filter will remove:
Particles with a diameter of 2.2 microns
The unit of resistivity is:
MQcm
The electrical resistance measured between opposite faces of a 1.00 cm cube of an aqueous solution at a specified temperature is termed:
Resistivity
According to CLSI, the resistivity of clinical laboratory reagent water (CLRW) must be:
> 10 MQcm
Which of the following should not be stored in borosilicate glass because it will etch the inside surface of the glass container?
Strong bases (caustics)
Low actinic glassware has which of the following properties?
High thermal resistance with an amber or red color added as an integral part of the glass
Care must be taken before selecting polyethylene plastic for use as test tubes and disposable transfer pipettes because?
Polyethylene can bind or absorb proteins, dyes, stains, and picric acid
Which of the following classes of glassware, including pipettes, is manufactured and calibrated to deliver the most accurate volume of liquid?
A
A to deliver to TD pipettes are designed to:
Drain by gravity
Which of the following devices is used to calibrate laboratory thermometers?
Gallium melting point cell
Convert 75 mg/dL to mg/L
750 mg/L
Convert 70.0 mg/dL glucose to mmol/L glucose
3..89 mmol/L
If a thermometer reads 39F, what is the equivalent degree C?
3.9C
Convert 200 picograms to grams
2.0 x 10-10 grams
A patients calcium result is 8.0 mg/dL. Conver this result to mmol/L
2.0 mmol/L
The surface area of a laboratory bench measures 12 square feet. What is the surface area in square meters?
1.115 square meters
A 24 hours stool specimen weighs 0.50 pounds. What is the weigh tin kilograms?
0.2265 kilograms
A 1 to 4 dilution must be prepared to make a total volume of 100.0 uL. How much serum must be used?
25ul
A patients creatinine is outside the linear range of the analyzer; 10ul of serum is added to 90.0 ul of diluent and the diluted sample is reanalyzed. The creatinine value of the diluted sample is 1.0 mg/dL. which of the following creatinine values is correct?
10.0 mg/dL
If 10 ml of sample is added to 190ml of diluent, what is the dilution factor?
20
A serum creatinine kinase is diluted 1/200 with a result of 50 U/L. What is the patients actual amylase result?
10,000
How many grams of sodium hydroxide (NaOH) are required to prepare 250 ml of a 1.00 molar solution?
10.0g
What is the concentration in mg/dL of a 140 mEq/L sodium standard?
322 mg/dL
Convert 145 mEq/L sodium standard to mmoles/L
145 mmol/L
What is the molarity of a 20.0% w/v glucose solution?
1.11 molar
Convert 40C to F
104F
What is the concentration (g/dL) of a 1/10 dilution of a 12% NaCl solution?
1.20
A solution contains 45 g/100 ml of glucose. It is diluted 1/10 and rediluted 1/10. what the concentration of the final solution?
0.45 g/100mL
How many milliliters of a 2.0M solution is required to prepare 50 ml of a 0.3M solution?
7.5 ml
Calculate the chloride concentration in milliequivalents per liter of a solution prepared by diluting 20 g of barium chloride to 1L.
192.0 mEq/L
Electromagnetic radiation exists both as Maxwells waves and as streams of particles called:
Photons
Amplitude of the electromagnetic sine wave is defined as:
The length of the electronic vector at maximum peak height
A nanometer is equivalent to:
10-9 meters
What is the concentration of creatinine in a serum sample if given the following:
Atest: 0.240
Astandard: 0.125
Cstandard: 0.90 mg/dL
1.7 mg/dL
Which of the following types of light sources emits radiation that changes in intensity very slowly as a function of wavelength?
Continuum source
A mercury lamp is an example of which of the following light sources?
Line source
Filters and diffraction gratings are examples of which of the following?
Monochromators
The wavelength in nanometers at peak transmittance is termed:
Nominal wavelength
Bandpass is defined as:
The total range of wavelengths transmitted
A photomultiplier tube functions to produce which of the following?
Increase the electronic signal produced as photons cascade from dynode to dynode
Didymium and holmium oxide filters are used to assess:
Wavelength accuracy
Which of the following is a cause of stray light failure in a spectrophotometer?
Room light entering the spectrophotometer and impinging upon the detector
Light reflecting off a urine dipstick absorbent surface is an example of which of the following?
Diffuse reflectance
A reflectometer measures which of the following?
A constant fraction of the reflection from a surface
Which of the following describes atomic absorption spectroscopy?
The absorption of monochromatic electromagnetic radiation by an element in its ground state with a net zero charge
Which of the following statements best illustrates the difference between photons from florescent emission and the excitation photons?
Emission photons are lower energy and longer wavelength
The polarization of light in fluorescent polarization immunoassay allows the measurement of which of the following?
Bound fraction in the presence of the free fraction
Oxidation of acridinium esters by hydrogen peroxide in the presence of peroxidase produces which of the following?
Chemiluminescence
Turbidimetry is the measurement of the reduction in light transmission caused by:
Particle formation
The presence of particles in a urine sample measured by a refractometer will result in which of the following?
A change in the critical angle of the light as it passed through the solution.
Which of the following accounts for the temperature rise in freezing point osmometry?
Heat of fusion
Which of the following electrical devices senses the freezing point of a solution in an osmometer?
A thermistor
Throughput is defined as:
Numbers of tests performed per hour
Which of the following statements best describes discrete testing?
Measures only the test requested on a sample
Any specimen, by a command to the processing systems, can be analyzed by any available process, in or out of sequence with other specimens, and without regard to their initial order describes which type of sample processing principle?
Random access analysis
A designated area where a limited number of specific tasks are completed describes which of the following terms?
Work Station
Which of the following devices is suitable to detect clots in serum specimens?
Pressure transducer
A liquid level sensor is designed to detect which of the following?
The presence of a sample by measuring the electrical capacitance of the surrounding area
A glucose result is falsely elevated and it was discovered that the previous sample on the sample carousel has abnormally high serum glucose. which of the following can cause this error?
Carryover
Which of the following statements best describes unit test reagents?
There is sufficient reagent present of the performance of a single test
A closed reagent chemistry analyzer:
Will not allow the operator to use reagent from other manufacturers
Which of the following represents a disadvantage to acquiring and implementing total laboratory automation?
The initial costs are very high
Which of the following terms is associated with the following description? A combination of a specimen manager with instruments or consolidated instruments of chemistry and immunoassay reagents that provide a broad spectrum of analytical tests.
WorkCell
A pneumatic tube delivery system is designed to provide the laboratory with which of the following functions?
Point to point delivery of patient specimens
Increase test throughput, reduce turnaround time, and compensate for staff shortages are all examples of which of the following?
Factors that drive automation
Automating laboratory testing has resulted in which of the following?
A reduction in the number of laboratory errors
Which of the following is carried out during the preanalytical stage of laboratory testing?
Specimen processing
Peltier thermal electric module functions to:
Maintain a constant temperature environment for the reaction curve.
Which of the following is an example of software that allows a laboratory to connect their existing LIS and instrumentation to facilitate sharing information and performs tasks not currently done with laboratories existing hardware and software?
Middleware
Direct tube sampling by automated analyzers eliminates the need to perform which of the following tasks?
Pour off specimens into another container
A test menu is:
A listing of all the tests or analytes that the instrument is capable of measuring.
Recapping/storage/retrieval are all examples of tasks performed during which of the following?
Sample processing
OSHA standards are written in which of the following documents?
Codes of Federal Regulations (CFRs)
When referring to quality control results, what parameter usually determines the acceptable range?
The 95% confidence interval for the mean
A class "A" fire involves:
ordinary combustible material including paper and wood
Which of the following quality control rules would be violated 1 out of 20 times by chance alone?
22S
A 22S quality control rule violation is defined as:
Two consecutive control values that exceed +or- 2s.
Which statement listed below is a reason to reject an analytical run?
Two consecutive control greater than 2 standard deviations above or below the mean.
Which of the following is an example of an inferential statistic?
Student T test
Which of the following plots is best for detecting all types of quality control errors?
Levy-Jennings
Which of the following practices is inappropriate when establishing quality control ranges?
Exclusion of any quality control results greater than +or- standard deviation from the mean
Liquid nitrogen is an example of which of the following:
Cryogen
Which of the following statistics is used to qualify the strength of the relationship between two variables?
Correlation Coefficient
An important difference between parametric statistics and nonparametric statistics is that parametric statistics presumes a Gaussian distribution, whereas nonparametric statistics:
is distribution free
Which of the following statements best defines accuracy?
The closeness of the agreement between the measure value of an analyte to its true value
A type 1 error is defined as which of the following?
Erroneously rejecting the null hypothesis or proclaiming a difference to exist when one does not
The letters MSDS represent which of the following?
Material safety data sheet
The label identification system designated NFPA 704-M represents which of the following warnings?
Chemical hazards
Least squares, demings, and passing and bablok are examples of:
Regression analysis
Sources of nonionizing radiation include which of the following?
Microwaves, tungsten-halogen lamps, xenon lamps
A blood borne pathogens protocol designed to help prevent accidental exposure of laboratory personnel is found in which of the following plans?
Exposure Control Plan
Analysis of variance (ANOVA) is an appropriate statistics to evaluate three or more sets of data among each other, but it does not reveal:
Which set of data is not in agreement with the other data
Linear regression analysis by least squares reveals:
Systematic and proportional error
The McNemar statistics using a two by two contingency table is useful for evaluating which of the following?
Correlation between two qualitative assays
Linearity is useful for assessing:
Slope and intercept of an analytical method
The term patient demographics refers to which type of information that is entered into a laboratory information system?
Patient specific information, for example, name, age, and date of birth
A cross reacting compound in a serum sample may result in which of the following?
A discordant result
Proportional error in a method is characterized by which of the following?
The magnitude of the error increases as the concentration of analyte increases
Bidirectional interface between the laboratory information system (LIS) and a chemistry analyzer provides which of the following?
The LIS can simultaneously transmit or download information to a laboratory instrument and the instrument can transmit data to the LIS
A glucose result that is lower than the detection limit of the method should be reported as which of the following?
Less than the detection limit value
Which of the following statements describes the proper method of storing chemicals in the laboratory?
According to their chemical properties and classifications
The results of a precision study are shown below. What is the percent coefficient of variation for the study?
mean- 100mg/dl
SD- 2.5 mg/dl
Variance- 6.25 mg/dl
2.5%
Reverse osmosis is a suitable process to complete which of the following?
Purify water
The to deliver (TD) pipette is designed to drain by:
gravity
One technique for monitoring water purity is to measure the ______ of an aliquot of water
Resistivity
Polypropylene, polyethylene, polycarbonate, and polystyrene beakers and flasks are all examples of:
plastic ware
Low actinic glassware is:
Amber or red in color, and the contents are visible
How many grams of H2SO4 are present in 1.5ml of a concentrated acid solution with a specific gravity of 1.80 and an assay purity of 95.0% w/w?
2.56
A serum lipase is diluted 1/20 with a result of 30 U/L. What is the patients actual lipase result?
600 U/L
A patients calcium result is 7.8 mg/dL. convert this result to mmol/l
1.95
A thermistor is an example of:
a device in which resistance changes as temperature changes
Swinging bucket and fixed angle head rotors are found in which of the following?
Centrifuges
Which of the following represents an alternative to mercury filled thermometers?
Thermometers containing an organic red spirit and pressurized with nitrogen gas, thermometers containing blue biodegradable liquid( isoamylbenzoate and dye), digital thermometers with stainless steel stems.
Which of the following calibration devices is used to verify the accuracy of laboratory thermometers?
SRM 1968 gallium melting point cell
Which of the following is an example of a photodetector?
photomultiplier tube
A holmium oxide filter is used to determine which of the following?
wavelength accuracy of a spectrophotometer
Diffuse reflection occurs on which type of surface?
grainy or fibrous
Light energy that occurs when a specific compound absorbs EMR, becomes excited, and returns to an energy levels lower than the original levels, describes which of the following?
Fluorescence
The release of light energy by a molecule after reacting with chemical is termed
chemiluminescence
The total solute concentration of a urine samples can be determined by
refractometry
Osmometry is based on measuring changes in the colligative properties of solutions. which of the following is an example of a colligative property of a solution?
freezing point
Which of the following is identified with the functional principle of a pH electrode?
potentiometry
Retention time in gas chromatography is defined as:
The time it takes after a sample injected onto a column from the column
What are the three major components of a mass spectrometer?
Ion source, mass analyzer, ion detector
Which of the following is an example of a type of transducer used in biosensor devices?
Opitical
Alpha, prime, and N are three factors that:
Affect chromatographic resolution
What is the energy in Joules of an x ray photon with a wavelength of 2.70 angstroms?
7.36 x 10-16
Determine the concentration of a solution in mg/dl given the following:
AbsUnknown: .200
AbsStandard: .100
Concentration Standard: 50
100.0
Blood lead is measured using an electrochemical technique known as anodic stripping voltammetry. Identify, in order of occurrence the three significant steps in anodic stripping voltammetry.
reduction and deposition of lead onto an electrode, resting sep, stripping lead off the electrode.
Which of the following is an example of a preanalytical sample processing task?
sorting sample
Which of the following are considered demands place on the lab that serve to drive automation?
reduced turnaround time, increased throughput, and compensates for staff shortages in the lab.
automating lab testing has resulted in
a reduction in testing errors
An open reagent analyzer allows the user to do which of the following?
Buy and use reagents from a vendor other than the instrument manufacturer.
Sample and reagent can be incubated using which of the following?
water, peltier thermoelectric modules, and heating air
The postanalytical stage of testing begins:
after the electrical signal is generated by the detector
Total lab automation is described as:
a combination of several instruments, consolidated instruments, and a work cell that are coupled to a specimen management and transportation system as well as process control software to automate a large percentage of lab work
The difference between work cells and workstations is that a work cell:
incorporates more than one type of testing platform, thus providing a broad spectrum of analytical tests.
Automated analyzers detect clots in samples by:
using a pressure transducer
Proportional error is characterized by which of the following?
The magnitude of the error increases as the concentration of analyte increases.
Which method of the following statements best describes the proper method of soring chemicals in the laboratory
According to their chemical properties and classifications
Cumulative trauma disorders (CTDs) are described as which of the following?
disorder associated with the overloading of particular muscle groups from repeated use
Which of the following statements defines a 22s quality control rule violation?
Two consecutive control values exceed +or-2s
A lab measurement that is less than the detection limit should be reported as which of the following?
less than the detection limit value
Establishing a reference interval requires which of the following?
A well defined group of individuals
Which of the following actions represents the best course of action for a 13s quality control failure?
Do not release patient results and rerun the control material that failed.
The presence of a cross reacting compound in a serum sample may result in which of the following?
a discordant result
the linearity of a method is characterized by which of the following?
slope and intercept
Match the following physical and chemical properties with ethane, C2H6, or sodium bromide, NaBr.
a.) Boils at -89*c-------ethane
b.) Burns vigorously in air ------- ethane
c.) Is a solid at 250*c --------- NaBr
d.) Dissovles in water -------- NaBr
How are the hydrogen atoms arranged in space in methane, CH4?
The FOUR bonds between carbon and hydrogen in CH4 are as far apart as possible, which means that the hydrogen atoms are at the corners of a tetrahedron.
Identify the following properties as more typical of organic or inorganic compunds:
a.) C6H12O6---------
b.) K3PO4---------
c.) I2--------
d.) C2H6S---------
e.) C10H22------------
f.) CH40-------------
Identify the following properties as more typical of inorganic or organic compounds:
a.) is soluble in water -------inorganic
b.) has a low boiling point ---organic
c.) contains carbon & hydrogen ------organic
d.) contains ionic bonds ------- inorganic
Identify the following as formulas of organic or inorganic compounds:
a.) KCl ---- inorganic
b.) C4H10 ----- organic
c.) H2O4 ----- inorganic
d.) CaCl2 ------ inorganic
e.) C3H7Cl ------ organic
Indicate whether the following properties are more typical of organic or inorganic compounds:
a.) is not soluble in water -------organic
b.) has a high melting point ------inorganic
c.) burns in air -------- organic
Heptane used as a solvent for rubber cement, has a density of 0.68g/mL and boils at 98*c. Draw the condensed structural formula.
CH3-CH2-CH2-CH2-CH2-CH2-CH3 Heptane
identify the class of compounds that contain each of the following functional groups:
a.) a hydroxyl group attached to a carbon chain: alcohol
b.) a carbon-carbon double bond: alkene
c.) a carbonyl group attached to a hydrogen atom: aldehyde
d.) a carboxyl group attached to two carbon atoms: ester