What are the 5 major functions of the kindney?
1) Remove waste products; primarily nitrogenous wastes from protein metabolism and acids, 2) Retention of nutrients, such as: electrolytes, protein, water, and glucose, 3) Acid-base balance, 4) Maintain water and electrolyte balance, 5) Hormone synthesis (erythro protein, renin, vitamin D)
Two, kidney bean-shaped organs located on the back of the abdominal cavity near the spinal column
The principal function of the kidney is:___________, Other functions include: ______
The formation of urine; regulate water, acid/base, and electrolyte balance
The formation of urine involves the removal of waste products from the blood (_____), and the retention of essential substances (______)
What are the six major parts of the kidney?
the capsule, cortex, medulla, renal pelvis, renal arteries, and renal veins
Funnel shaped tubules 10 to 12 meters long, muscular organs that go from the kidneys to the back of the bladder at a slight angle
What are the functions of each layer of the capsule?
Intermost First Layer- directly surrounds the kidney, Second Layer- middle layer of fat that protects the kidney, Outermost Third Layer- surround kidney and anchors it to surrounding structures
This area of the kidney contains the functional filtering units of the kidney called the nephron units
Each nephronis made up of the: (5)
glomerulus, proximal convoluted tubule, loop of Henle, distal convoluted tubule, and collecting ducts
Afferent arterioles take blood ____ the kidney, while efferent arterioles take blood _____ the kidneys
to, away from
What is the job of the proximal convoluted tubule?
To reabsorb substances before they are excreted in the urine
The maximum amount of an analyte that will be reabsorbed from the glomerular filtrate and controls the amount which is reabsorbed
The reddish brown inner region of the kidney that contains the collecting tubules and renal pyramids
Collect the urine formed by the nephrons and carry it to the ureters; found in the medulla
Triangular structures foudn in the medulla and serve as collecting points for all the collecting tubules of the nephron units
Explain the final reabsorption of sodium in order to maintain water/electrolyte balance
Final reaborption of sodium takes palce in the distal convoluted tubule. Renin, an enzyme, is released. Released Renin forms angiotensin and causes the secretion of aldesterone. Kidneys, in response to the aldesterone, actively retains sodium and passively retains water
In the distal convoluted tubule, excess acid is also removed from the body. This helps in:
maintaining the body's pH balance
Long, straight portions of the nephron after the distal convoluted tubule that lead to the renal pelvis, and establishes the final concentration of urine while under the control of APH
This is released when sodium concentration is high in an effort to prevent additional water loss
A funnel shaped cavity in the kidney that funnels the urine from the collecting tubules to the ureters
These blood vessels carry the blood from circulation to kidneys; carrying the blood that is going to be filtered
These are the veins carrying blood away from the kidneys; carrying the blood that is going to be filtered
What is the funciton of the urinary system?
To filter out certain substances fromt he blood such as waste products and excess fluids
What are the three main processes involved in urine formation?
1) Filtration, 2) Reabsorption, 3) Secretion
Having more solids in the blood, the higher the presssure. As a result, a filtering of material will be from _____ to _______
An area of high pressure, an area of lower pressure
The filtrate is essentially free of _____. Why?
Plasma protein and blood cells, the molecules are large and only smaller molecules can make it through the glomerulus
The movement of a molecule from low area of concentration to a high area of concentration
The movement of molecules from an are of high concentration to an area of low concentration
The level of substance that is greater than the reabsorption capacity of the kidney and the excess substance remains in the urine filtrate
When the concentraion of a certain substance in the blood becomes too high, it may be _____ from the kidneys to the urine; also used to eliminate substances that are too large to be filtered by the glomerulus
What is the primary purpose of secretion?
To regulate acid-base balance via secretion of hydrogenious and maintain the 7.4 pH of blood
The concentration of the dissolved elements in urine varies based on which criteria? (5)
dietary intake, physical activity, metabolism, hormones, and body position
Urine samples should be collected in a ________ w/ a ________
clean disposable container, screw top lid
If the specimen cannot be delivered to the lab w/ in 30 min, it should be _____ for up to ______
refrigerated, 8 hrs
What is the best method of preservation for short periods of up to 8 hours, or during a 24-hour urine collection?
If a urine is preserved using refrigeration, what must you make sure to do before analysis?
The sample must be brought back to room temp.
Preservation in which preservatives are added to the urine either after or during collection
For the best result, which method of urine preservation should be used?
Both should be used together for best results
Preferred characteristics of chemical preservatives include: (4)
Bactericidal, inhibits urease activity, preserves formed elements, does not interfere w/ testing
Preservative used to preserve the cellular materials found in urine; may cause false positive test for glucose
Preservative used to maintain pH to help preserve cellular and chemical elements of the urine; also retard bacterial growth
Preservative that is a convenient method w/ controlled concentration of chemicals to minimize interference
Commercial Preservative Tablets
Changes in unpreserved urine include:
Increase in bacteria, turbidity (precipitation of amorphous sediments); Decreased ketones, bilirubin (exposure to light), urobilinogen (due to oxidation); Deterioration of formed elements, Color change due to oxidation/reduction of metabolites
What are the effects of increased bacteria?
deteriorate specimen, urea to ammonia, increase pH, may use up glucose as a food source, nitrates to nitrites, increased turbidity
A random specimen requires a minimum of what volume? Collected in?
10-15 ml. a non-sterile container @ anytime of the day
What do you do if an abnormal finding is collected in a random urine sample?
Have the patient recollect under more controlled conditions
A first morning specimen is essential for:
preventing false neg pregnancy tests and evaluating orthostatic proteinuria
The patient is instructed to void two hours after consuming a normal meal describes which urine specimen?
Two-hour post prandial
Two hour post prandial urines are used to test ______ and to maintain patients w/ _________
glucose, diabetes mellitus
During a glucose tolerance test, a _______ is collected and tested for glucose before a glucose tolerance test is performed
fasting urine sample
24 hour urine samples are collected often for a ______ than a ______
quantitative analysis, qualitative analysis
In a 24 hour urine sample, is the first morning sample collected as well? 1st morning? 2nd morning?
No, the first morning urine is voided and discarded
Yes, the urine is voided and added to the previously collected period
Performed when a patient is at risk to infection or perforation or the urethra or bladder by the physician or nurse inserts a catheter (hollow tube) in the urethra of he bladder
Catheterized specimens are primarily used for:
microscopic examinations and microbiological cultures
A safer, less traumatic method of obtaining urine for bacterial culture, also offering a more representative and less contamination
Mid-Stream Clean Catch
How does a midstream differ from a MSCC specimen?
A midstream collection is the same as a MSCC except, a sterile container is not required and the external genitalia do not have to be washed
Sample in which a needle is placed directly into the bladder through the abdomen to obtain urine for bacterial culture or cytological exam
What are the methods that may be used to get urine from a pediatric patient that is not "potty-trained"?
Sterile plastic bags, cath, or suprapubic
Factors that affect the volume of urine excreted in a 24 hour period are?
fluid intake, fluid loss, diuretics (tea or coffee), and pathologic states (diabetes, renal failure, and obstruction)
Which of the following does not increase output of urine: Drugs, caffiene, alcohol, diabetes mellitus, and diabetes insipidus
None of the above, all increase output of urine
Specimens should be reported as _____ only when no pigmentation can be seen when viewed against a white background
A urine that can be seen through easily is reported to have an appearance of ______ and is usually indicative of:
Clear, normal dilute urine
A urine that can be seen through w/ difficulty and is reported as _______ and indicative of:
Hazy, small amounts of phosphate, urates, or cellular material (normal if stored properly, WBCs or RBCs in high amounts (abnormal))
A urine that cannot be seen through is reported to have an appearance of ______ and is usually indicative of:
Cloudy, large amounts of phospate, urates or cellular material (normal if stored properly, WBCs or RBCs in high amounts (abnormal))
A urine sample that cannot be seen through, nor will light pass through is reported to have an appearance of ______ and is usually indicative of:
Turbid (Opaque), WBC/RBC , epithelial cells, bacteria
What is used to calibrate the refractometer? Confirm that calibration?
DI water, 5% NaCl or 9% sucrose
A high S.G. may indicate _______, while a low S.G. may indicate _________
concentrated urine due to dehydration or high dissolved substances; diluted urine due to high fluid intake or kidney disease, diabetes insipidous, low ADH
What is the purpose of the microscopic exam indices of urine?
Detect and identify insoluble materials present in urine
A microscopic examination of urinary sediment must include both a ______ and _______ of the elements present
identification and quantification
Why must a urine sample be fresh or adequetly preserved for microscopic examinaion?
formed elements may disintegrate rapidly, particularly in alkaline urine
If a stain is being used for a microscopic urine examination, it should be added _______ the specimen is agitated for resuspension
During a microscopic examination, first a scan should be done to get a feel for the general composition and larger casts. This should be done on:
During a micrscopic examination, the actual identification should take place after the initial scan on the:
How many fields should be examined during a microscopic examination: low power? high power?
10 low power, 10-20 high power
Finding a few occasional RBCs is considered _______ while finding of more than occassional may indicate:
Normal; kidney or genitourinary tract damage
What may cause females in particular to display large numbers of RBCs?
if collected during menstration
In concentrated or hypertonic urine, RBCs may appear to have spiny projections, also called ______
Crenated RBCs are a result of:
osmotic pressure removing the intracellular fluid, causing the cell to collapse or shrink
RBCs that swell and shrink rapidly, releasing their hemoglobin content and leaving only the cell membranes
Any marked increase or large amount (outside the small numbers normally found) of WBCs is termed:
In hypotonic urine the cytoplasmic granules of WBCs appear to exhibit Brownian movement. These cells are called _______.
Large, flat, irregular shaped cells w/ a small, central, distinct nuclei and abundant cytoplasm; originate from lining of the vagina and the lower portion of the male and female urethra w/ little pathological significance
3x the size of WBCs; appear round or pear-shaped w/ a central nucleus and may have tail-line projections; originate from the lining of the renal pelvis, bladder, and upper urethra; seldom pathological
Round w/ an eccentrically located nucleus, slightly larger than leukocytes; may be flat, cubadil, or columnar; line the proximal and distal convoluted tubule
An increased number of Renal Tubular Epithelial Cells indicate __________
Tubular necrosis, tubular damage, or renal graft rejections
What conditions must be met in order for casts to form?
Decreased pH, Reduced urine flow, Increased protein, High soluble concentration
-Appear colorless and transparent
-Have same refractive index as urine
-0-2/lpf considered normal
-May be seen following exercise, dehydration, and heat
-Increased in glomerulonephritis, pyelonephritis, chronic renal failure, congestive heart failure
-Yellow to brown
-Associated w/ any condition that damages the glomerulus, tubules, or renal capillaries
-Indicative of bleeding w/ in the nephron and primarily associated w/ glomerulonephritis, lupus nephritis, subacute bacterial endocarditis and focal glomerulitis
-Refractile and exhibit granules
-Multi-lobed WBCs within w/ visible nuclei
-Indicative of inflammation or infection w/ in the nephron
-Finding occassional cast is not significant
-When epithelial cells slough off from the tubules and adhere to or become incorporated in hyaline casts
-Only present in cases of tubular damage and necrosis
-Usually swollen and tinged w/ yellow/brown color
Epithelial Cell Cast
Epithelial cells that are arranged irregularly indicates that they:
originated from different portions of the tubule
-These casts result from the degradation of cellular casts or the aggregation of serum proteins filtered by the glomerulus
-Initially granules appear large and coarse, and then break down into fine granules as urine flow is decreased
Is it important to differentiate between coarse and fine granular casts? Why or why not.
No, differentiation between coarse and fine granular casts is not important. They are usually just reported out as granular casts.
-Yellow, gray, or colorless casts
-Smooth, homogeneous appearance
-Broad w/ blunt or broken ends
-Edges either cracked or serrated
-Indicates extreme decrease in urine flow and chronic renal failure
-When the breakdown of epithelial lining of the tubules leads to the production of fat droplets instead of granules
-Contain yellowish-brown fat droplets or oval fat bodies
-Indicate disorders causing lipiduria, such as nephrotic syndrome
A positive identification of fatty casts can be made by:
using polarized light to look for Maltese Cross Formations
-Much larger than other casts
-Formed in the collecting ducts
-Indication of renal failure
A blood fluke that dwells in the veins around the bladder, having a characteristic terminal spine
Findings of E. vermicularis in a urine sample would suggest what?
fecal contamination. E. vermicularis normally resides in the folds of the rectum
Parasite that is flattened on one side and rounded on the other; known to cause nephrotic syndrome
These can be found occassionally in urine following sexual intercourse or as a result of nocturnal emissions, and are easily identified based on their head and tail shape
Sperm cells (spermatozoa)
True or False: The prescence of spermatozoa in urine is never significant
False. Spermatozoa within a urine specimen can sometimes be significant and should be reported according to the OI
Appears as threadlike structures w/ a low refractive index and is considered NOT clinically significant
If uric acid crystals are present in fresh samples, the possibility exists that this is present somewhere in the renal system
-crystal w/ appearance as a diamond or rhombic prisms, occasionally have six sides
-Increase levels seen in leukemia, Lesch nyhan syndrome and gout
-Appear in a non-crystalline form as a granular precipitate
-Give urine a cloudy pink color
How do you differentiate between amorphous phosphates and amorphous urates?
Based on pH of the urine or by the addition of alkali or heat; amorphous urates are soluble in alkali and heat
-Generally seen as colorless, octahedral (box shaped) crystals resembling small squares crossed by two intersecting diagonal lines ("envelope" appearance)
-May also appear as dumbells or spheres
-Usually a result of diet rich in oxalic acid
How can you differentiate calcium oxalate and calcium carbonate?
Dilute HCl can be added to differentiate
Normal crystals found in alkaline urine include:
Triple Phosphate, Amorphous Phosphates, Calcium Phosphates, Ammonium Biurate, Calcium Carbonate
-Colorless prisms w/ three to six sides, often referred to as "coffin lids"
-Soluble in dilute acetic acid
-Appear as a granular precipitate w/ no definite shape
-Soluble in dilute acetic acid
-Appear as colorless, thin prisms, plates, or needles
-Not frequently seen in urine but, normal in alkaline urine
-Precipitated only when free ammonia is present due to bacterial metabolism in long-standing specimens
-Appear as spherical bodies covered w/ long, irregular spicules
-Soluble in acetic acid or heat
-If acetic acid is added to urine in which Calcium Carbonate crystals are present, what will the result be?
Gas will form
-colorless, highly refractile, hexagonal plates w/ equal or unequal sides
-Occur frequently in cystinuria, an inborn metabolic error
-Large, flat, rectangular, transparent plates w/ a notch in one or more corners
-Referred to as a characteristic "missing corner"
-Indicates excessive tissue breakdown
-Oily, refractive, yellow or brown spheroids possessing radial and concentric striations
-Seen in individuals w/ liver disease
-Very fine, highly refractile needles that occur in sheaves or clusters and are constricted in the middle
-Black in color, esp. in center
-Appear in sever liver disease
-An artifact that resemble casts but are tapered at one end
-Formed at the junction of the ascending loop of Henle and the distal convoluted tubule
-Have same clinical significance as casts
List some examples of contaminants that may be found in the microscopic evaluation of a urine specimen
Fecal contamination, wood fibers, oil droplets, starch granules, pollen grains, cotton, hair, talc granules
Which crystals are considered ALWAYS clinically significant?
Tyrosine, Cystine, Cholesterol, Leucine
What is used to lyse RBCs when identification of other structures is obscured such as yeast?
2% acetic acid
Plastic strips w/ individual pads impregnated w/ reagents that react w/ the constituents in urine describes which method of urine examination?
Most dipsticks are designed to measure: (10)
Glucose, Bilirubin, Ketones, Specific gravity, Blood, pH, Protein, Urobilinogen, Nitrite, Leukoasterase
For the dipstick method, the strip must be adequetly moistened for how long?
1 second, also called 'wetting'
Drawing the strip over the edge of the container, touching to an absorbent paper, and holding the strip _______ are all recommended to prevent _______ throughout the dipstick procedure
What are the criteria for storing and preserving strips?
-Store in a tightly capped container @ recommended temps
-Moisture, direct light, heat, or volatile substances will deteriorate the strips
-Do not use past their expiration date
-Check for discoloration and dispose if it is present
When must positive and negative dipstick controls be run?
each day patient testing occurs and when new reagent bottles are opened
Methyl red detects pH changes in the range of:_____________, while bromthyl blue detects changes in the range of: __________
4.4-6.2 (red-yellow); 6.0-7.6 (yellow-blue)
What is of concern to the pH test pad if excess urine remains on the dipstick?
Urine may run off the nearby protein pad onto the pH pad
What are the possible sources of error for the dipstick pH testing method?
-Delayed processing can cause alkaline urine
-Run-off from the protein pad can cause falsely acidic
What is the confirmatory test for pH?
There is no confirmatory test for pH. But if an exact measurement of urine pH is needed, a pH meter is used
This serum protein is most frequently present in the urine in kidney disease where proteinuria is involved, making up 60-90%, due to low molecular weight
These proteins are in some diseases, particularly multiple myeloma
Abnormal globulins (BENCE-JONES proteins)
Proteins that may be present in urine include:
Plasma proteins, serum proteins, albumin, bence-jones proteins, Tamm-Horsfall proteins, mucus, and protein from prostatic, seminal, and vaginal secretions
True or False: Proteinuriais not always indicative of renal disease
True. However, its prescence in urine does require additional testing to determine if the protein is normal or pathologic
Major causes of proteinuria include:
Glomerular membrane damage, tubular damage, pre-renal disorders, increased serum levels, renal proteinuria, orthostatic proteinuria, microalbuminuria
Benign proteinuria can be produced by conditions such as:
exposure to cold, strenuous exercise, high fever, dehydration, orthostatic or postural proteinuria
The prescence of protein is related to the body position in the patient; protein is present in long periods in a vertical position and disappears when a horizontal position is assumed
How is a diagnosis of orthostatic proteinuria made?
The patient is asked to collect a urine sample upon rising in the morning, and then collect a urine sample after several hours remaining in a vertical position. The first morning specimen will be negative for protein while the second specimen will be positive.
Procedures for the determination of urinary proteins are divided into three groups including:
screening tests (dipstick), semi-quantitative tests, and quantitative tests
The protein test on the dipstick uses the principle of __________. Explain.
Protein error of pH indicator. Test is based on the ability of proteins to alter the color of some acid-base indicators w/o changing the pH
The protein pad on the dipstick contains a ________ indicator. At a pH of 3, abscence of protein will cause a _______ color, and the presence of protein will cause a ______ color
Tetrabromphenol blue, yellow, green and then blue
What are the possible sources of error for the protein dipstick test?
-Highly alkaline urine causes blue color change not related to protein
-Prolonged contact will cause blue color change not related to protein
-Stongly pigmented urines
-Proteins other than albumen present, due to low specificity of strips
Does the protein dipstick test determine the presence of all protein?
No. The dipstick is more sensitive to protein albumin and less sensitive to globulins, hemoglobin, Bence-jones, or mucoproteins. A negative result does not rule out the presence of these other proteins.
What is the difference between the measurements of the microalbumin strip and the protein reagent strip?
Units for Microalbumin reagent strip are mg/L
Units for protein reagent strip are mg/dL
All positive urines for protein will be followed by the semi-quantitative method called _________, which is a type of ________
Sulfosalicylic Acid (SSA); precipitation test
Sources of error for the SSA test include:
-Uncentrifuged, turbid specimens
-Highly alkaline urines
A low molecular weight protein that is produced in patients w/ multiple myeloma; an immunoglobulin (IgD) that can be found in urine
Two methods that can be used to detect Bence-Jones protein are:
electrophoresis and immunoelectrophoresis
Although _______ is the most commonly found sugar in urine, __________, ________, _______, and ______ may also be found under certain conditions
Glucose.; lactose, fructose, galactose, and pentose
What kind of specimen is best for a glucose test? Why?
Fasting specimen is best because glucose may appear in urine following a meal
The two types of tests most frequently used to detect glucose are:
1) enzymatic test, 2) reduction tests
Explain the principle of the glucose test using the dipstick
Based on the double sequential enzyme reaction called "glucose oxidase procedure", producing a color
Sources of error for the dipstick method of glucose detection include:
-Contamination w/ strong oxidizing agents
-Trace value in dilute specimen
-Strips exposed to air
-High Ascorbic acid (Vitamin C)
Can the dipstick test be used to detect sugars other than glucose?
No. The dipstick test is specific for glucose and can ONLY be used to test for glucose.
What is the principle of the Clinitest?
ability of glucose and other sugars to reduce copper sulfate in the presence of alkali and heat
Historically, the copper reduction test for glucose detection used a reaction mixture called ______; today the principle used is put into the ________
Benedict's solution, Clinitest tablet
When using the Clinitest a negative result will produce __________ while a positive result will produce _______
a blue color, a green/yellow/orange/brick red color
Sources of error for the Clinitest include:
-High ascorbic acid (vit C)
-Radiographic contrast media
-Mixing test tube before the 15 sec wait after bubbling stops
What is the difference between the Reagent Strips and the Clinitest for glucose detection and how they are affected by vitamin C (ascorbic acid)?
False neg - Reagent strip
False pos - Clinitest
Which is a more sensitive method for detection of glucose: the Clinitest or the dipstick
The dipstick is more sensitive than the Clinitest
What can cause a strong positive dipstick and a negative Clinitest?
What can cause a positive Clinitest and a negative dipstick?
Strong oxidizing agents
Sugars other than glucose such as Galactose, Fructose, Pentose, and Lactose
Which sugar is most clinically significant and of concern when found in the urine of newborns? Why?
Galactose, it represents an "inborn error of metabolism" and can result in a failure to thrive and other complications
Which test should be performed w/ the glucose oxidase on all infant urines? Why?
the Clinitest, to detect the presence of any Galactose
There are three types of ketone bodies including:
1) Acetoacetic Acid-2%, 2) Acetone-20%, 3) Betahydroxybutric acid-78%
Ketone are a normal finding in the urine of healthy individuals. True or False.
False. Ketones are not normally found in the urine of healthy individuals
The most commonly used test for the detection of ketonuria is:
Sodium nitroprusside test of Rothera, most commonly on the dipstick
The dipstick method detects _________, but not _______ or ________ rather assuming ther presence. Why?
Acetoacetic Acid, acetone or betahydroxybutric acid. These two are simply derived from acetoacetic acid and are therefore assumed to be present if acetoacetic acid is there.
For detection of urine ketones:
Chemstrips do not measure _____________
Multistix/Ketostix do not measure ________
acetone or betahyroxybutric acid
Sources of error for the ketone dipstick test include:
-Highly colored urine
-Improper preservation or left at room temp too long leads to breakdown of acetoacetic acid by bacteria
What is the confirmatory test for urine ketones but, may also be used for serum, plasma, or whole blood?
The presence of blood is (abnormal/normal?) and is a good indicator of:
abnormal; renal dysfunction or kidney or urinary tract trauma
Hematuria is often a result of ______________, while Hemoglobinuria may be a result of _______
disease or trauma to the kidney or urinary tract, lysis of the RBCs already in the urinary tract or by intravascular hemolysis
The most accurate way to detect blood in urine are ________, such as ________ although they cannot differentiate between hemoglobinuria or hematuria.
Chemical test, dipsticks
What can be done to differentiate hematuria from hemoglobinuria if a dipstick is positive for blood?
microscopic examination. intact RBCs can be seen in a microscopic examination and dipstick chemical testing while free hemoglobin can only be detected through chemical testing
The dipstick test for blood in the urine is based on the peroxidase-like activity of hemoglobin as it acts like an enzyme, also called ____________
Although a speckled pattern on a dipstick may indicate the presence of _______, and a solid color may indicate the presence of ______, it cannot be definitive which is present simply based on the dipstick test
True or False: Differentiation can be made between hematuria and hemoglobinuria based on the dipstick test results alone.
False. The presence of blood in the urine may be determined in one of its two states but, microscopic evaluation is required to differentiate between the two.
Sources of error for the blood reagent strip include:
-Strong oxidizing agents
-Microbial peroxidase assoc. w/ UTI
-Blood from menstruation
-Testing supernatant after centrifugation
-Elevated S.G. or protein cause RBCs to lyse
-Ascorbic Acid (Vit C)
-Captopril (antihypertensive meds)
-High nitrite levels in UTIs
Why is the normal urine bilirubin considered to be negative even though normal urine bilirubin is about 0.02 mg/dl?
Screening tests for bilirubin are not sensitive enough to detect this amount, so the normal urine bilirubin is considered negative
Increased levels of bilirubin in the urine are a often a result of:
Liver diseases such as hepatitis and cirrhosis and bile duct obstruction
Reagent tablets to detect bilirubin (Ictotest) may be used w/ either ______ or _______
serum or urine
The principle behind the reagent tablet and the dipstick of bilirubin testing is the:
This is impregnated in the dipstick pads and reacts w/ bilirubin in urine to produce a color
Sources of Error of the Dipstick test for bilirubin include:
-Lodine (drug) metabolites
-Indican: waste product
-Oxidation of bilirubin to biliverdin (Exposure to UV light)
- Ascorbic Acid
-Elevated nitrite levels, UTI's
All positive and questionable results of bilirubin should be tested using the confirmatory test for bilirubin, the ____________
The most common error in using the Ictotest to detect bilirubin is:
using specimens that are not fresh, bilirubin is rapidly destroyed by light
Sources of error for the Ictotest to detect bilirubin include:
-Exposure to room air makes bilirubin undetectable due to oxidization
Bacterial action w/ in the intestinal tract convert bilirubin to a group of compounds known as ______
For urobilinogen, small amounts are excreted in the ________ but the majority of it is excreted in the ______
Urobilinogen urine output is increased in:
liver disease and hemolytic disorders
liver obstructions and antibiotic therapy when intestinal bacteria are reduced
In the modified Ehrlich reaction, this reacts w/ urobilinogen in a strongly acid and a color enhancer to produce results
PABA (Ehrlichs reagent)
What is specific about the type of urine used for the dipstick urobilinogen test?
only strongly acid urines will produce a result, alkaline urines will not produce a result
Explain the detection and reporting of the reagent strip used for urobilinogen detection
Reagent strips cannot detect the absence of urobilinogen. Concentrations of 0.2-1.0 EU/dl are reported as normal, while concentration about 1.0 are reported as 2.0-12 EU/dl.
Which manufacturing type of dipstick uses Diazo reaction and diazo salt to react w/ urobilinogen?
Sources of Error for the dipstick method of urobilinogen detection include:
-Ehrlich reactive compounds
-Aldomet (anti-hypertensive drug)
-Pigments and their metabolites
-Tested @ room temp rather than body temp- "warm aldehyde reaction"
-Oxidation to urobilin (delayed testing)
-Most result from exposure to light
-Random samples; urobilinogen excreted w/in 2-3 hrs following meal
What is the confirmatory test for urobilinogen?
There is no confirmatory test for urobilinogen but if confirmatory testing is needed to be done it should be done w/ another reagent strip that uses a different methodology
The nitrite rapid chemical test provides a quick screening for the presence of which condition? And also evaluate?
UTI; effectiveness of antibiotics and evaluate high risk patients for a UTI
Are nitrates a normal finding in the urine of healthy patients?
Yes, nitrates derived from diet are normally found in the urine of healthy individuals
Explain the clinical difference in nitrates and nitrites
Nitrates derived from diet are normally found in the urine of healthy patients however, common UTI organisms contain enzymes that reduce nitrate in the urine to nitrite. This makes the presence of nitrite abnormal and indicates the presence of an infection.
Nitrite dipstick test, like that of the urobilinogen test, will only produce a result if the sample is __________, a ____________ sample will not produce a result
A uniform pink color on a nitrite test yields a _________ result, while a spotted pink or pink-edged also yields a _____ result
What does a positive result on the nitrite dipstick method indicate?
The presence of 100,000 or more organisms (bacteria) per ml
Sources of error for the nitrite dipstick detection test include:
-Old urine, resulting in more bacteria
-UTI cause by gram pos bacteria
-Insufficient time in bladder
-Insufficient dietary nitrate to convert
-Too much bacteria reduce nitrite to nitrogen
Any shade of pink on a nitrite dipstick test indicates a clinically significant amount of bacteria. True or False.
Nitrite dipstick test, tests UTI that are onset by:
Gram negative bacteria converting nitrate to nitrite
What is the confirmatory test for Nitrite?
A bacteriological culture and microscopic exam of sediment are the only confirmatory test
It is important that even vague clinical symptoms of UTIs found in a nitrite test are followed up by:
a urine culture
This test detects the presence of leukocytes, screening for possible UTI and inflammatory process
What is the principle behind the dipstick leukocyte test?
Using Diazo reaction: enzymatic reaction using the esterase in leukocytes, reacting w/ diazonium salt to produce purple color
More standardized: Chemical tests or sediment exams for leukocytes. Give an example of why.
Chemical test are more standardized. It would detect leukocytes that have been lysed and would not have been found in a microscopic exam.
A positive leukocyte esterase test w/ no WBCs or bacteria in the microscopic analysis could be caused by:
Chlamydia spp., Trichomonas spp.
Sources of error for the leukocyte esterase dipstick test include:
-Highly pigmented urine
-High glucose and protein
-Antibiotics (cephalexin, cepalothin, tetracycline, gentamicin)
-Oxalic acid (metabolite of Vit. C)
While the Clinitek, Atlas, and IRIS are all example of automated urine analyzers, this is the only one that can identify cellular constituents in place of performing a microscopic analysis
What are the advantages and reasons for automation of urinalysis?
-Some eliminate the need for microscopic analysis by identifying cellular constituents
True or False: Automated urinalysis machines eliminate transcription errors
False, they reduce transcription errors but, does not eliminate them entirely
What are the advantages of LIS?
-reduce transcription errors,
-decrease turnaround time
Link of instruments and personal computers in the laboratory describes which aspect of LIS?
Ability to verify and finalize patient results before sending to the provider describes which aspect of LIS?
If past and present results do not correlate, there will be a flag on the tech's workstation to prompt them to investigate possible causes, this is called a _________
True or False: Two advanced functions of a LIS include standardization of results from different tests onto one standardized report form, as well as patient lab test history
There are three different general categories of renal function tests including:
1) Concentration tests
2) Retention tests
3) Clearance tests
This category of renal function test are helpful in measuring the capacity of the kidney to remove certain substances present in the blood
The type of clearance test to be used is based on the functional aspect of the kidney that is to be evaluated. Some substances are removed by _________ while others are by ________ and _______.
Glomerular filtration alone, glomerular filtration and tubular secretion
______ is an example of a substance that is primarily removed by the glomerulus and measures ___________. Meanwhile, ______ is an example of a substance that is filtered out by ______ and also ________, so it measures _____________.
Creatinine, GFR; Urea, glomerulus, reabsorbed by the tubules, renal function
Which renal function test, the clearance or the BUN test, is more sensitive to a change in kidney function?
Most sensitive chemical method and accurate measurement of glomerular filtration rate
Creatinine clearance test
The creatinine clearance test estimates the blood flow through the kidneys per _________ w/ the complete removal of creatinine
Explain the significance of increased values from a creatinine clearance test
Increased values have no clinical significance and if it occurs a source of error must be suspected
The most common causes for a decreased clearance test result are:
damage to the glomerulus (glomerulonephritis) or damage to the renal tubules (tubular nephritis), as well as reduced renal perfusion (blood flow) to the glomerulus
A waste product formed in muscle and brain tissue as a result of the breakdown of creatine
Creatinine is formed in the liver, removed from the blood by ________, and (is/is not) reabsorbed by the tubules; therefore nearly all of creatinine is excreted in the urine
Glomerular filtration, is not
The amount of creatinine produced is dependent on and proportional to:
an individual's body muscle mass
In a 24-hour period, for healthy individuals creatinine is produced and excreted at:
a constant rate w/ little variance
True or False: Creatinine concentrations can be influenced by diet, hydration, or protein metabolism
False, creatinine concentrations are not influenced by diet, hydration, or protein
The creatinine levels in combination w/ the ______ has been used to differentiate between:
BUN, Prerenal and renal causes of azotemia
Sources of error for the creatinine clearance test include:
-Non-creatinine chromogens elevate results
-Excessive heat and pH elevate results
-Improper urine collection
-Entire volume not collected
What are the specimen requirements for a creatinine clearance test?
-24hour urine, timing crucial
-volume measured in ml
-one serum specimen required
What is the creatinine clearance formula? What does each part represent?
U/S X V/1440 X 1.73/SA
U = Urine creatinine concentration mg/dl
V = 24 hour volume in ml
S = serum concentration mg/dl
1440 = number of min in 24 hrs
1.73 = body surface of adult
SA = patients body surface using chart
These tests measure how much of a specific substance is being retained in the blood by the kidneys
The major end product of protein metabolism, derived principally from the amine groups of amino acids
Term used to refer to an increase in the plasma concentration of non-protein nitrogen compounds such as urea, uric acid, and creatinine
Increases in nitrogen compounds as measured by urea levels, may be due to ________ (______), ______________ (_______), or _________(_________)
Pre-renal (before kidney), renal (kidney) or post-renal (after kidney) causes
Factors that may cause increase in BUN levels may be water depletion, increased protein breakdown, high protein diet, inadequate blood flow to the kidneys, reduced filtration, and heart failure
Factor that increases BUN are reduced glomerular filtration due to acute or chronic renal disease
Factors that increase BUN levels include all types of urinary tract obstruction such as renal stones, tumors, or an enlarged prostate gland
Sources of error for the BUN procedure include:
-Unpreserved urine, bacteria convert urea to ammonia
Increased urea levels can result from:
-High protein diet
-Reduced renal perfusion
What may be done to prevent false decrease in BUN if a preservative is needed?
Preserve w/ HCl or toluene
Semen analysis is usually requested by the provider for: (3)
post-vasectomy cases, infertility studies, medico-legal cases
Semen is composed of fluid from four different areas of the body including what? what percentage?
Bulbourethral glands (5%)
Testis and Epididymus
Seminal Vesicles (60%)
Collection methods for semen analysis include:
Use of condom that has been washed (Not for fertility studies)
Before collection of semen for analysis, the patient must abstain from sexual contact for at least how many days?
Semen samples must be delivered to the lab w/ in _____ of collection and kept @ _____
30 min, 35-37C
When recording time for semen samples it is important to record:
The time the specimen was collected, not received
The dilution factor for semen analysis is _____ using a diluting fluid that consists of:
1:20, sodium bicarbonate, formalin, DI water
How long is the charged hemacytometer let sit in a moist petri dish to allow the spermatozoa to settle?
What is the calculation for a sperm count?
avg # sperm counted x dilution factor x 1000 = million sperm/mL
Sperm motility observation is recorded by the percent of sperm demonstrating __________
A minimum motility of _____ and a quality of _____is considered normal w/ in ______ of collection
50-60%, fair, 3 hours
Semen analysis is determined by:
macroscopic, sperm count, sperm motility, sperm morphology and other additional tests
If abnormal sperm morphology exceeds 10% following a sperm count:
a semen smear is prepared and stained
Sperm morphology should be reported from a _____ specimen under which objective?
stained, oil immersion
The most common additonal tests that may need to be performed on abnormal semen analysis are?
sperm viability, seminal fluid fructose level, and sperm agglutinins
Explain post vasectomy semen analysis.
Looking for presence or absence of sperm. Tested until 2 consecutive specimens have no sperm seen. Results reported as 'no spermatozoa seen' OR 'spermatozoa seen'
an infection of the nasal mucous membranes due to allergies characterized by increased percent of eosinophils in nasal secretions
Collection methods that are acceptable for a nasal eosinophil smear include:
Sneezing/Blowing Nose into waxed paper, cellophane, parafilm; Cotton tipped applicator; Aspiration of nasal secretions w/ a bulb
The three stains that are acceptable for nasal eosinophil smears are:
Wright's, Hansel's, and Eosin w/ methylene blue
Explain the evaluation of the smear of a nasal eosinophil.
-Low power first- EOs and WBCs
- Oil immersion next- scan @ least 10 fields, counting all EOs and WBCs
What is the formula to find the percentage of nasal eosinophils?
total # eosinophils counted x 100/total WBCs counted = % eosinophils
Normal eosinophils range from: _____ and a percentage greater than ____ is indicative of _____
3-10%, 10%, allergic rhinitis
Does the absence of eosinophils in a nasal smear rule out allergic rhinitis?
No, there may be a secondary sinus infection or there may have been no recent exposure to the causative agent
What aer the functions of the CSF?
-Supplies nutrients to nervous tissue
-Removes metabolic waste
-Cushions the brain and spinal cord against trauma
How many mls of CSF are produced ever hour? total volume of adults? neonates?
20 mls, 140-170 mls, 10-60 mls
a vascular fringe-like fold of the pia mater located in the third, fourth, and lateral ventricles of the brain; where CSF is formed; has membranes that are semipermeable selective filters; acts as a blood brain barrier
How is CSF collected? by whom?
Collected by lumbar puncture between the 3rd and 4th, or the 4th and 5th lumbar vertebrae by the physician
Meninge: delicate connective tissue w/ tiny blood vessels and is the only meninge attached to the brain
What are the functions of the meninges?
-Protect blood vessels and close venous sinuses
-Form paritions w/ in the skull
In adults, how much spinal fluid will be obtained from the lumbar puncture? infants?
5-10 mL, 0.5-1 mL
Any leftover fluid obtained by a lumbar puncture is stored. How?
In a refigerator or freezer for 7-10 days
How many tubes of CSF are drawn and where do they get sent?
3; Tube1-Chem and Sero, Tube 2- Micro, Tube 3- Hematology
In protein fraction CSF, electrophoresis method uses _____ as its medium of choice followed by staining w/ ______
agarose gel, Coomassie blue
This can be seen on agarose gel in _____ of patients w/ multiple sclerosis when evaluating CSF protein fractions
95%, Oligoclonal banding
Elevated CSF protein can be cause by:
Low CSF protein can be caused by:
Meningitis and hemorrhage
Leaking from the CNS
Increased CSF glucose is seen in:
plasma glucose values increased, diabetic coma
Bacterial meningitis, Insulin shock
CSF culture is not an diagnostic test for meningitis, as much as it is a _________
Due to the small number of organisms that may be present in the CSF, this should be done to prevent false negatives
Counter-immunoelectrophoresis is used to detect:
-Group B. Strep
Latex agglutination is used to detect:
-Group B strep
-H. influenzae type B
-E. coli k1 antigens
-Cryptococcus neoformans in serum and CSF, more sensitive than India Ink
--False pos- interference w/ rheumatoid factor
For hematology, the appearance of CSF is examined for _____, _____, and ________. Normal spinal fluid should be _____, ______, and contain _______. Cell counts and diffs are also done.
color, appearance, clot formation
clear, colorless, no clots
Appearance of CSF in hematology:
Xanthochromic (pink, yellow, orange):
clear, colorless, like water
release of Hgb from hemolyzed RBCs; must be tested w/in one hour
Should be noted, could indicate traumatic tap or meningitis