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Clin lab test 1

lab tets, PFT, ABG, CXR
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what can cause false results in MCV testing
Hyperglycemia, extreme leukocytosis, presence of cold or warm agglutins, extreme leukocytosis
what does an increased RDW mean
RDW = red cell distribution width is normally 11.5 - 14.5%
if high it means there is an increased variability in red cell size (anisocytosis)
WBC with dif or CBC with dif
count of white blood cells per volume of blood
normal for men and non-pregnant women: 5K-10K per cubic mm or
5.0 -10.0 x 10^9 per liter
differential part looks at composition which should be:
neutrophils 50%
band neutrophils 3-6%
lymphocytes 25-40%
monocytes 3-7%
eosinophils 0 - 3%
basophils 0 - 1%
RBC
count of number of red blood cells per volume of blood
Normals:
M should be 4.5 - 5.5 million RBCs/mcL
W should be 4.0-5.0 miliion RBCs/mcL
Children should be 3.8-6.0 million RBCs/mcL
newborns should be 4.1-6.1 million RBCs per mcL
hematocrit
measures the RBC in a given volume of whole blood
Men: 42%-52%
Women:36%-48%
Children:29%-59%
Newborns: 44%-64%
hemoglobin (Hgb)
measures amount of oxygen-carrying protein in the blood
Men: 14-17.4 grams per deciliter (g/dL)
Women: 12-16 g/dL
Children:9.5-20.5 g/dL
Newborn: 14.5-24.5 g/dL
In general, a normal hemoglobin level is about one-third the value of the hematocrit
MCV- mean corpuscular volume
measurement of the average size of your RBCs. normally 82-98 cubic millimeters

elevated when your RBCs are larger than normal (macrocytic), for example in anemia caused by vitamin B12 deficiency.

When decreased, your RBCs are smaller than normal (microcytic) as is seen in iron deficiency anemia or thalassemias.
MCH - mean corpuscular hemoglobin
calculation of the average amount of oxygen-carrying hemoglobin inside a red blood cell. normally 26-34 picograms (pg)

Macrocytic RBCs are large so tend to have a higher value, while microcytic red cells would have a lower value.
mean corpuscular hemoglobin concentration
calculation of the average concentration of hemoglobin inside a red cell. normally 32-36 grams per deciliter (g/dL)

Decreased values (hypochromia) are seen in conditions where the hemoglobin is abnormally diluted inside the red cells, such as in iron deficiency anemia and in thalassemia.

Increased values (hyperchromia) are seen in conditions where the hemoglobin is abnormally concentrated inside the red cells, such as in burn patients and hereditary spherocytosis, a relatively rare congenital disorder.
platelet count
the number of platelets in a given volume of blood. normally 140K-400K per mm^3 in adults and 150K-450K per mm^3 in chldren

Both increases and decreases can point to abnormal conditions of excess bleeding or clotting.
mpv - mean platelet volume
Mean platelet volume (MPV) is a machine-calculated measurement of the average size of your platelets. normally: 7.4-10.4 mcm^3

New platelets are larger, and an increased value occurs when increased numbers of platelets are being produced. gives information about platelet production in your bone marrow.
blood smear
looks at blood on a slide plate/smear to determine if cells are normal in shape, size, color and number
drugs that can increase WBC count
Allopurinol
Aspirin
Chloroform
Corticosteroids
Epinephrine
Heparin
Quinine
Triamterene
drugs that can lower WBC count
Antibiotics
Anticonvulsants
Antihistamines
Antithyroid drugs
Arsenicals
Barbiturates
Chemotherapy drugs
Diuretics
Sulfonamides
why would you order a WBC/
cbc
symptoms such as fatigue or weakness or has an infection, inflammation, bruising, or bleeding
leukocytosis
elevated number of white blood cells
can result from bacterial infections, inflammation, leukemia, trauma, intense exercise, or stress
leukopenia
decreased white blood cell count
can result from many different situations, such as chemotherapy, radiation therapy, or diseases of the immune system
protein, albumin, globulin (serum)
also known as total protein
determines the amount and types of protein in the blood

Normal values:
*Total protein: 6.4 - 8.3 g/dL
Albumin: 3.5 - 5.0 g/dL
Alpha-1 globulin: .1 - .3 g/dL
Alpha-2 globulin: .6 - 1 g/dL
Beta globulin: .7 - 1.2 g/dL
Gamma globulin: .7 - 1.6 g/dL
Normal A/G ratio: slightly over 1
causes of false results in total protein/albumin/globulin serum test
abnormal draw
pregnancy
drugs: estrogen, cotricosteroids, anabolic steroids, growth hormone, insulin, chlorpromazine (schizophrenia), isoniazid (TB), phenacemide (antiepileptic), salicylates, sulfonamides, tolbutamide
high total protein values are indicative of
-Chronic inflammation.
-Hepatitis B or C
-HIV.
-Possibly bone marrow disorders (multiple myeloma, Waldenstrom's Disease-polycythemia).
-High A/G ratio reflects underproduction of immunoglobulins
-Genetic deficiencies.
-Some leukemias.
low total protein values are indicative of
-Liver disorder.
-Kidney disorder.
-Malnutrition.
-Bleeding (hemorrhage).
-Extensive burns.
-Conditions that cause malabsorption (Celiac disease, Inflammatory Bowel Disease IBD).
-Low A/G ratio:
Due to overproduction of globulins
-Multiple myeloma.
-Autoimmune diseases.
Due to underproduction of albumin
-Cirrhosis
-Kidney disease (nephrotic syndrome, glomerulonephritis)
uric acid serum
looks at amount of uric acid in blood, used as screening for gout and kidney disease

Normal values: 3.4-7.0 mg/dL in adult men, 2.4-6.0 mg/dL in post menopausal women, 2.0-5.5 mg/dL in children
things that can cause false results in uric acid serum
Diets high in protein and/or foods containing purines, recent alcohol consumption, and certain medications (such as anti-inflammatory drugs or aspirin)
high uric acid serum levels indicate
hyperuricemia, gout, renal disease/failure, kidney stones, leukemia, potential precursor for hypertension, Lesch-Nyhan syndrome
low uric acid serum levels indicate
rarely seen and are not commonly considered cause for concern
BUN, creatinine (serum)
used to assess kidney function
Normal values:
BUN Values: 6-20 mg/dL
Creatinine (serum): .8-1.4 mg/dL
BUN-Creatinine ratio: 10:1-20:1
extremely high BUN creatinine serum levels can indicate
moderate to severe renal failure or other serious diseases
things that can affect BUN/creatinine serum level
medications
ingesting large amounts of protein within 24 hours prior to test
high levels of BUN in blood serum can indicate
-impaired kidney function due to acute/chronic kidney disease, damage, or failure.
-Decreased blood flow to the kidney could be another cause for an increased concentration of urea in the blood.
-congestive heart failure, gastrointestinal bleeding, hypovolema, heart attack, shock, conditions that cause obstruction of urine flow, dehydration, stress, lack of protein in diet
high levels of creatinine in blood serum can indicate
acute tubular necrosis, dehydration, diabetic nephropathy, eclampsia, glomerulonephritis, kidney failure, muscular dystrophy, preeclampsia, pyelonephritis, reduced kidney flow, rhabdomyolysis, or a urinary tract obstruction.
a high BUN:creatinine ration of >20:1 indicates
problem is located BEFORE the kidney
low levels of BUN in blood serum can indicate
severe liver disease, malnutrition, over hydration
low creatinine levels in blood serum are seen in
late stages of muscular dystrophy and in myasthenia gravis
a low BUN:creatinine ration of <10:1 indicates
a problem WITHIN the kidney
lipid profile
can also be called lipid panel or coronary risk panel
normal values
LDL: less than 100mg/dL
Total Cholesterol: less than 200mg/dL
HDL: 60mg/dL or higher in both sexes
Triglycerides: less than 150mg/dL
panic values for lipid profile
LDL: greater than 190mg/dL
Total Cholesterol: greater than 240mg/dL
HDL: less than 40mg/dL in men and less than 50mg/dL for women
Triglycerides: greater than 500mg/dL
lipid profile must be performed
after 9-12 hour fast
things that may cause false results in lipid profile
1. Eating a meal less than 8 hours before a lipid test will increase cholesterol levels.
2. Very fatty meals, such as those eaten around the holidays, can increase cholesterol levels for up to two weeks.
3. During pregnancy, women experience an increase in cholesterol levels
what high values in lipid profile can indicate
High LDL, Total Cholesterol and Triglycerides: indicate an increased risk for heart disease.
Depending on other risk factors, these high levels may require treatment.
High HDL (good cholesterol) levels show a decreased risk for heart disease.
what low values in lipid profile can indicate
Low HDL levels indicate an increased risk for heart disease.
Low LDL, Total Cholesterol and Triglycerides show a decreased risk for heart disease.
PTT (prothrombin time) / aPTT (activated partial thromboplastin time)/ INR (international normalized ratio)
blood test that determines clotting time

normals:
11-13.7 seconds(PT)
21.33 seconds (PT if pt on therapeutic thinners)
2.0 - 3.0 (INR)
2.5-3.5 (INR therapeutic level for pt on thinners)
panic value for INR and for PTT
INR >5
PTT >100 seconds
special instructions for INR/PTT testing
if pt is on anticoagulants blood draw should be done prior to the pts daily dose of anticoagulant
things that can cause false results in INR/PTT
1. Some antibiotics can increase
2. Barbiturates, oral contraceptives and hormone-replacement therapy (HRT), and vitamin K (including multivitamins and any foods with large amounts of vitamin K) can lower
3. Alcohol can lower .
4. underdrawn lab sample could also cause a false result.
low values on a PTT/INR can indicate
at risk for a blood clot and complications from blood clots (pulmonary embolism, TIA, CVA...etc.)
The patients' blood is clotting too fast and could form blood clots.
high values on a PTT/INR can indicate
patients' blood is to too thin and/or the patient's blood is not clotting in a therapeutic amount of time.
medication should be adjusted to get them at a therapeutic level
low values on RBC/hemoglobin/hematocrit can indicate
Blood loss- traumatic, post surgical,
Bone marrow suppression from drugs
Hemoglobinopathies-sickle cell, thalassemia
Nutritional deficiencies - vitamin B12, iron and folate
Cancer-colon, gastric, metastases in the bone marrow, lymphoma
high values on RBC/hemoglobin/hematocrit can indicate
Chronic obstructive pulmonary disease (COPD)
Severe burns
Congestive heart failure
Polycythemia Vera,
Kidney disease
serum electrophoresis or serum globulin electrophoresis
blood test that looks at different proteins/globulins in the blood- can also be done as a random 24-hour urine sample but that is less common

test shouldd be done after a 4 hour fast

Normal values:
•total protein: 6.4 to 8.3 g/dL (about 0.5 g/dL lower in nonambulatory patients)
•albumin: 3.5 to 5.0 g/dL
•alpha1-globulin: 0.1 to 0.3 g/dL
•alpha2-globulin: 0.6 to 1.0 g/dL
•beta-globulin: 0.7 to 1.2 g/dL
•gamma-globulin: 0.7 to 1.6 g/dL
•Serum globulin: 2.0 to 3.5 g/dL
•IgM component: 75 to 300 mg/dL
•IgG component: 650 to 1850 mg/dL
•IgA component: 90 to 350 mg/dL
things that may cause false results in serum electrophoresis
pregnancy
dehydration
burns
infection
drugs: corticosteroids, neomycin, salicylates
what high values in serum electrophoresis can mean
different proteins indicate different disease but the below are some of the options:
o Acute infection
o Heart, kidney, liver disease
o Dehydration
o Pregnancy
o Infection
o Chronic inflammatory disease (rheumatoid arthritis, systemic lupus erythematosus)
o Hyperimmunization
o Multiple myeloma
o Waldenstrom's macroglobulinemia
what low values in serum electrophoresis can mean
different proteins indicate different disease but the below are some of the options:
o Disease of immune system (lupus, rheumatoid arthritis)
o Cancer (leukemia, lymphoma, multiple myeloma
o Dehydration
o Crohn's disease
o Heart, kidney, liver, lung disease
o Infection
o Hypothyroidism
o Pregnancy
o Starvation/severe dieting
o Severe burns
bleeding time test
test is done by inflating a BP cuff and making 2 incisions on the arm below cuff- incision is blotted every 30 seconds and the time when the bleeding stops is recorded

done to determine platelet function

normal value: 8 minutes
things that can cause false results in bleeding time test
drugs: blood thinners
what can high values in bleeding time test indicate
thrombocytopenia
von Willebrand disease
Glanzmann's thrombasthenia
Bernard-Soulier syndrome
storage pool disease
fibrinogen deficiency
renal disease
dysproteinemias
vascular or platelet disorders
what can low values in bleeding time test indicate
non specified
bleeding time test reliability
not often used any more due to lack of sensitivity and specificity and it's inability to predict risks of surgical bleeding
platelet count/thrombocyte count
normal values 150,000-450,000/microliter
ordered to test for bleeding disorders or bone marrow diseases
panic values for platelet count
<20K/microliter
can cause spontaneous bleeding and is considered a life threatening risk
things that may cause false results in platelet count
number of things that can increase platelet levels:
high altitudes
strenuous exercise
being post-partum
drugs: estrogen and OCP
decrease in platelet levels can be seen in women before their menses
what do high platelet counts indicate
>400K/microliter indicates thrombocytosis
what do low platelet counts indicate
<100K/microliter or a decrease of >50% indicates thrombocytopenia
serum electrolyte normal values
Normal values:
Sodium: 136-144mEq/L;
Potassium: 3.7-5.2mEq/L in adults (3.4-4.7mEq/L in children);
Chloride: 101-111mEq/L in adults (90-110mEq/L in children);
Carbon Dioxide (Bicarbonate): 20-29mEq/L
panic values for serum electrolyte test
Sodium: <125, >160mEq/L;
Potassium: <3.0, >6.0mEq/L;
Chloride: <80, >120mEq/L;
Carbon Dioxide (Bicarbonate): <10, >40mEq/L;
Anion Gap: >30mEq/L
things that can cause false results in serum electrolyte test
potassium levels can be falsely elevated by several different specimen-collection or processing errors
what high sodium in serum electrolyte test may indicate
dehydration, Cushing's syndrome, Diabetes Insipidus, kidney disease or trauma, hyperaldosteronism
what high potassium in serum electrolyte test may indicate
damage to kidneys, severe burns, crushing injuries, heart attack, and diabetic ketoacidosis, too much acid (pH) in the blood makes potassium in the body's cells "leak" out of cells and into the blood, ACE inhibitors cause high potassium levels
what high chloride in serum electrolyte test may indicate
dehydration, too much salt in diet, kidney disease, overactive parathyroid gland
what high bicarb in serum electrolyte test may indicate
dehydration (vomiting), recent blood transfusion, overuse of medicines that contain bicarbonate (especially antacids), anorexia, chronic obstructive pulmonary disease (COPD), fluid in the lungs (pulmonary edema), heart disease, Cushing's disease, Conn's syndrome
what low sodium values in serum electrolyte test may indicate
sweating, burns, severe vomiting or diarrhea, drinking too much water, or poor nutrition; underactive adrenal glands or thyroid gland, heart failure, kidney disease, cirrhosis, cystic fibrosis, or SIADH (syndrome of inappropriate antidiuretic hormone secretion)
what low chloride values in serum electrolyte test may indicate
syndrome of inappropriate antidiuretic hormone secretion, Addison's disease, metabolic alkalosis, heart failure, ongoing vomiting
what low potassium values in serum electrolyte test may indicate
hyperaldosteronism, severe burns, cystic fibrosis, alcoholism, Cushing's syndrome, dehydration, malnutrition, vomiting, diarrhea and certain kidney diseases, such as Bartter's syndrome, diuretics cause low potassium levels
what low bicarb values in serum electrolyte test may indicate
hyperventilation, aspirin or alcohol overdose, diarrhea, dehydration, severe malnutrition, severe burns, shock, liver or kidney disease, a massive heart attack, hyperthyroidism, uncontrolled diabetes
anion gap
-a value calculated using the results of an electrolyte panel; it evaluates the difference between measured and unmeasured electrical particles (ions or electrolytes) in the fluid portion of the blood.
-the number of positive ions (cations) and negative ions (anions) should be equal. However, not all ions are routinely measured.
-this value will represent the unmeasured ions and primarily consists of anions
abnormal anion gap can indicate
certain kinds of metabolic abnormalities such as starvation, diabetes or presence of a toxic substance.
HIV ELISA and western blot test
common test for HIV testing

normal value is negative result, indicating patient's blood doesn't have HIV antibodies
how does HIV ELISA and western blot test work
1. A blood sample is obtained and sent to the lab.
2. The ELISA is used to detect HIV antibodies and a positive ELISA result is always followed by a Western blot test.
3. A positive Western blot test confirms HIV infection.
4. A negative Western blot means the initial ELISA was a false positive.
5. Western blot tests can also be inconclusive in which case further testing must be done.
- bes sure to remember the window period between infection and detection of HIV antibodies
false positives in HIV ELISA test can be caused by
Certain conditions such as syphilis, lyme disease, and lupus
false negatives in HIV ELISA test can be caused by
If a patient is tested for HIV too soon after the initial infection with HIV, a false negative may result.
This "window period" can last up to 3 months. Patients with an early HIV infection, also called an "acute" or "primary" HIV infection will often have a negative test result.
patients who should be given HIV ELISA test
- pts who ask to be tested
-pts with unusual infections seen in the immunocompromised
- pregnant women (b/c it can be passed to fetus or to baby through breast milk)
pts at high risk:
- men who have sex with men
- IV drug users and their sexual partners
serum immunoglobulin/ immunoelectrophoresis-serum test
measures the immunogloulins (antibodies) in the blood
normal values are having no monoclonal antibodies detected
panic values in serum immunoglobulin/immunoelectrophoresis-serum test
monoclonal antibodies detected in the serum sometimes may be due to certain types of cancer (multiple myeloma, chronic lymphocytic leukemia)
serum antibody tests
screen for specific antibodies in the blood
commonly screened antibodies include: HIV, HepB, H.pylori, aspergillus

normal antibodies are to have no antibodies
things that may cause false negatives in serum antibody tests
testing during the window period between infection and presence of significant amounts of antibodies
things that may cause false positives in serum antibody tests
a concurrent infectious disease
high values in serum antibody tests indicate
severity of the disease
d-dimer lab test
determines presence of thrombus, measures breakdown products of a blood clot

normally <250 ng/ml or <250 ug/L
things that may cause false positive results in d-dimer test
high levels of rheumatoid factor, bilirubin, triglycerides, and lipids
may also be higher in the elderly without being pathogenic
what high values in d-dimer test can indicate
there is abnormal fibrin degradation occurring in the body
normally plasma does not have detectable amounts of d-dimer fragments
can indicate DVT, PE
when to request a d-dimer
blood glucose/serum glucose
determines how much glucose is present in the blood, often done fasting

Normal values:
•70-99 mg/dL (3.9 to 5.5 mmol/L) is normal fasting glucose
•100-125 mg/dL (5.6 to 6.9 mmol/L) is considered impaired fasting glucose and may be predictive of diabetes.
•>126 mg/dL (7.0 mmol/L) on repeated tests indicates diabetes
•60-100mg/dL is considered within normal bounds for random capillary testing
panic values in blood glucose test
below 30mg/dL is considered severe hypoglycemia
Above 300 mg/dL is suggestive of diabetic ketoacidosis (DKA).
things that might cause false results in blood glucose test
uncalibrated glucometer
circulatory abnormalities in extremity where sample was taken
contamination of the dilution of the sample (i.e. with what was used to clean testing site)
when to order blood glucose test
signs or symptoms of hyperglycemia: polydipsia, polyuria, fatigue, blurred vision and slow healing infections
signs or symptoms of hypoglycemia: diaphoresis, polyphagia, muscle fasciculation, anxiety, altered mental status and blurred vision
high values in blood glucose test can indicate
• Diabetes
• Acromegaly
• Extremis (response to trauma, myocardial infarction or CVA/TIA )
• Chronic renal failure
• Cushing's syndrome
• Drugs: corticosteroids, tricyclic antidepressants, diuretics, epinephrine, estrogen, lithium, phenytoin, salicylates.
• Excessive food intake
• Hyperthyroidism
• Pancreatic cancer
• Pancreatitis
low values in blood glucose test can indicate
• Adrenal insfficiency
• EtOH consumption
• Drugs: acetaminophen, anabolic steroids
• Extensive liver disease
• Hypopituitarism
• Hypothyroidism
• Insulin overdose
• Insulinomas
• Starvation
homolytic complement test
often called CH50, CH100 for total or can look at different components- commonly C3, C4

Normal values:
Total blood component level (CH50): 41 to 90 hemolytic units
C1 level: 16 to 33 mg/dL
C3 levels: Male: 88 to 252 mg/dL Females: 88 to 206 mg/dL
C4 levels: Male: 12 to 72 mg/dL Female: 13 to 75 mg/dL
when is compliment test ordered
to help determine cause of unexplained inflammation
to determine if autoimmune disorder
to monitor the state of acute or chronic infections
to determine integrity of immune pathway
what high values in compliment test can indicate
certain infections
Chronic and acute inflammation
Cancer
Ulcerative colitis
what low values of CH50 in compliment test can indicate
deficiencies of C1-C9
if half the nomal value indicates a deficiency in C9
if 0 indicates deficiency in C1-C8
low values in C3 and C4 indicate
activation of classical pathways and alternate pathways
low values in compliment can indicate
Cirrhosis
Glomerulonephritis
Hereditary angioma (will also have low levels of C1 inhibitor)
Hepatitis
Kidney transplant rejection
Lupus nephritis
Malnutrition
Systemic lupus erythematosis
DAT
direct antibody test- detects RBC antibodies attached to red cells
IAT
indirect antibody test - detects unbound antibodies direced against RBC antigens other than the A and B antigens
when to perform IAT
prior to any anticipated blood transfusion and as a follow up to a transfusion reaction
part of every pregnancy work up
calcium/total calcium/ionized calcium
done to test levels of calcium in the blood

normal values:
Nonionized calcium in adults: 9.0 to 10.5 mg/dL or 2.25 to 2.75 mmol/L
Nonionized calcium in children: 7.6 to 10.8 mg/dL or 1.9 to 2.7 mmol/L
Ionized calcium in adults: 4.65 to 5.28 mg/dL
things that can cause false results for calcium serum levels
If pt has taken milk, antacid, calcium salt, or calcium supplements 8 hours before administering the test, since this will affect the test result.
Calcium values are high in children who are growing.
Calcium values are low in older men and pregnant women.
when to order calcium serum levels
screen for:
Parathyroid gland function • Kidney function • Kidney stones • Pancreatitis • Bone disease •
Find underlying cause of:
-Muscle spasms, depression, confusion, tingling around the mouth and fingers, and muscle cramping and twitching (can be caused by low calcium level in blood)
-abnormal electrocardiographic (ECG) result.
-Nausea, vomiting, bone pain, lack of appetite, weakness, abdominal pain, and constipation and increased urination (can be caused by a high calcium level in blood)
high values for calcium serum result can indicate
Hyperparathyroidism
Cancer metastasized to the bone
Kidney disease
That the patient has been on bed rest for a long period
Tuberculosis
Sarcoidosis
Addison disease
Dehydration
Hyperthyroidism
Paget disease
Chronic liver problems
Ingesting too much calcium, vitamin D, or vitamin A
Decreased phosphate blood level
what low calcium serum levels can indicate
Hypoparathyroidism
Malabsorption syndrome -Pancreatitis
Hypoalbuminemia
Low magnesium
Kidney disease
Increasing phosphate blood level
phosphorous or phosphate serum level
done to test levels of phosphorous in blood

Normal values:
Adults: 3.0 to 4.5 mg/dL or 0.97 to 1.45 mmol/L
Children: 4.5 to 6.5 mg/dL or 1.45 to 2.1 mmol/L
Children younger than 1 year of age: 4.3 to 9.3 mg/dL or 1.4 to 3 mmol/L
things that can cause false results in phorsphorous serum levels
ETOH ingestion within 12 hours prior to test
drugs ingested within 2 weeks of test: vit D, antacids, epinephrine, acetazolamide, anabolic steroids, photosphate based enemas
miscalibration of equipment
why to order phosphorous serum test
screen for bone disease, kidney disease, parathyroid gland function
what high values of phosphorous serum test can indicate
Pregnancy
Acromegaly
Hypoparathyroidism
Kidney disease
Diabetic ketoacidosis
Bone fracture that is healing
Excess vitamin D
Low level of magnesium
what low values of phosphorous serum can indicate
Osteomalacia
Malnutrition
Hyperparathyroidism
Low level of vitamin D
Liver disease
Sprue/celiac disease
Alcohol abuse
High level of calcium
Burns
phosphate and calcium have a _______ relationship
inverse
PTH, parathyroid hormone serum levels
done to determine amount of PTH in blood, usually done fasting for 10-12 hours and usually done early in the day

normal values:
10-65 picograms per mililiter pg/mL
things that may cause false results in PTH test
certain drugs can increase levels:
phosphates, anticonvulsants, steroids, isoniazid, lithium, rifampin
when to order PTH serum levels
if there is an abnormal calcium test or if pt exhibits symptoms of hypercalcemia (fatigue, nausea, abdominal pain, thirst) or hypocalcemia (abdominal pain, muscle cramps, tingling fingers)
Often ordered at intervals when someone has a disease that affects calcium regulation (parathyroid tumor) or other chronic disease (kidney disease)
what high values of PTH may indicate
Hyperplasia
Parathyroid tumor
Low calcium level in blood
Kidney disease
Pancreatic cancer
Lung cancer
Ovarian cancer
Absorption disorder of the intestines
Vitamin D deficiency
what low values of PTH may indicate
Lymphoma
Low magnesium level in blood
Excess calcium intake
Malfunctioning parathyroid gland
Multiple myeloma
rheumatoid panel/rheumatoid factor
normal value or negative titre is < 20u/mL and <1:20
negative titre indicates low probability of having RA
Rh Factor levels that are considered normal but indicate there is something going on
between 40-60u/mL or 1:80
often indicate RA
things that can cause false results in Rh factor testing
persistant viral, bacterial and parasitic infections
cancer
lung disease
liver disease
kidney disease
leukemia
multiple myeloma
TB
when to order Rh factor test
when person has symptoms or RA:
pain, warmth and stiffness in joints, it might also be ordered when evidence of the disease is noted from x-ray of the joints
to test for sjogrens
lyme titre
measure of how much of teh sample can be diluted before the antibodies to the disease can no longer be detected

normal values: less than 1:256, negative
panic value for lyme titre
greater than 1:256
false positives for lyme titre can be caused by
previous lyme infection
doesn't necessarily indicate an active infection
false negatives for lyme titre can be caused by
if tested during window between infection and accumulation of enough antibodies
when to order a lyme titre
when a patient displays symptoms of the disease and has recently been exposed
to a tick bite.
Symptoms include:
o "Bull's‐eye" rash - An expanding red rash with a pale center
o Exhaustion
o Fever
o Headache, stiff neck
o Muscle and joint pain
a thyroid or thyroid function panel usually includes which tests
looking at the amount of the following present in the blood:
Thyroid stimulating hormone
free T4 (thyroxine-unbound, active)
total T3 (triiodothyronine- bound, inactivated)
free T3 (triiodothyronine-unbound,active)
thyroid panel normal values
TSH: 0.5 to 4.7 mIU/L (milli-international units per liter)
T4: 58 - 140 nmol/L (nanomoles per liter)
FT4: 10.3 - 35 pmol/L (picomoles per liter)
T3: 0.92 - 2.78 nmol/L (nanomoles per liter)
FT3: 0.22 - 6.78 pmol/L (picomoles per liter)
when to order a thyroid panel
to assess thyroid function
when there are symptoms of thyroid dysfunction: weight gain, cold intolerance, hair loss, fatigue, increased heart rate, weight loss
what high values in the thyroid panel can indicate
hypothyroidism
(high TSH and low T3, T4)
what low values in the thyroid panel can indicate
hyperthyroidism
low TSH and high T3,T4)
what can cause inaccurate results in thyroid panel
exposure to mice (high TSH)
amiodarone (high TSH)
recent severe illness (high TSH)
glucocoriticoids, dopamine (low TSH)
old age (low TSH)
some systemic illnesses (low TSH)
joint fluid analysis or synovial fluid analysis
performed by arthrocentesis
looks at color/clarity, blood cell count, crystals and gram stain/culture of the fluid
synovial fluid analysis normal values
1. color/clarity: clear to light yellow, moderate viscocity
2. WBC's 4500-1000
3. RBCs 4.5 - 5.5 x 10^6 cells/ml male or 4.0 - 4.9 x 10^6 cells/ml female
4. crystals: non present
5. no bacteria and no organism grown in culture
when to order synovial fluid analysis
when patient has one or more swollen, read and/or painful joint
to monitor a known condition
abnormal color/clarity in synovial fluid can indicate
If red or contains red coloring then there is bleeding or an increased amount of RBC's within the joint. This could be from an injury or from a clotting disorder.
If milky white or cloudy, then there is either an increased number of WBC's due to infection or crystals associated with gout or pseudogout
abnormal blood cell counts in synovial fluid can indicate
~infection, illness, or trauma to the joint. ~if large number of neutrophils present could be a bacterial infection.
~if there are a large number (>2%) of eosinophils present, then something to keep in mind is Lyme's Disease
what crystals in synovial fluid can indicate
if MSU/uric acid can indicate gout
high concentrations of proteins found withing synovial fluid indicate
bacterial infection
decreased viscosity of synovial fluid indicates
inflammation
high levels of lactate dehydrogenase in synovial fluid can indicate
typical finding in RA and infectious arthritis
retinculocyte count
performed to assess the amount of reticulocytes in the blood at any given time

results are calculated as Reticulocyte %-#ret/#RBCx100.
Normal ranges are: Adults: 0.5% to 1.5%; Newborns: <7%; Normal values at birth: 2.5% to 6.5%.
reticulocyte counts higher than normal range can indicate
excessive bleeding, erythroblastosis fetalis(life threatening blood disorder in fetus/newborn), hemolytic anemia, or kidney disease with higher than normal erythropoietin production
reticulocyte counts lower than normal range can indicate
cirrhosis of the liver, folate,vitamin B-12, or iron deficiency, kidney disease with decreased erythropoeitin production, or a side effect from radiation therapy
ABG pH normal
7.35-7.45
ABG pH <7.35
acidotic
ABG pH >7.45
alkalotic
acidity and alkalinity of blood is regulated by
buffer response
can be due to respiratory regulation or metabolic regulation
respiratory regulatory buffer process
carbonic acid works as buffer
1. cell metabolism results in CO2 carried to lungs in blood
2. CO2 is combined with H2 to form carbonic acid (H2CO3)
3. blood pH changes according to amount of carbonic acid present and trigger lungs to increase rate and depth of ventilation until an appropriate amount of CO2 is re-established
renal regulatory buffer process
bicarb (increases pH)
1. kidneys excrete or retain bicarb which takes hours to days
2. as blood pH decreases, kidneys retain bicarb
3. as blood pH increases, kidneys excrete bicarb in urine
respiratory acidosis
a pH less than 7.35 with a PaCO2 greater than 45mmHg
respiratory acidosis process
1. hypoventilation results in accumulation of CO2 which combines with water in body increasing carbonic acid which decreases pH
symptoms of respiratory acidosis
•CNS depression (HI, Rx)
•Impaired respiratory muscle function (spinal cord injury)
•Pulmonary Disorders (atelectasis, pneumonia, pneumothorax, pulmonary edema, PE)
•Other (pain, chest wall injury)
respiratory alkalosis
pH greater than 7.45 with a PaCO2 less than 35mmHg
respiratory alkalosis process
results from hyperventilation

hyperventilation can be a result of:
• Psychological (anxiety, fear)
• Pain
• Increased metabolic demand
• Medications
• CNS lesions
symptoms of respiratory alkalosis
• Neurologic (lightheadedness, numbness, tingling, confusion, inability to concentrate, blurred vision)
• Cardiovascular: dysrhythmias, palpitations, dry mouth, disphoresis, tetany

Resolve by treating the underlying problem!
metabolic acidosis
Bicarb less than 22mEQ/L combined with pH less than 7.35
metabolic acidosis process
caused by either:

1. deficit of base as a reult of diarrhea or intestinal fistulas
or
2. increase of acid as a result of renal failure, diabetic ketoacidosis, anerobic process, metabolism, starvation, or salicylate intoxication
signs and symptoms of metabolic acidosis
1. CNS: Hedache, confusion, restlessness; later - lethargy, stupor, coma
2. Cardiovascular: dysrhythmias
3. Pulmonary: Kussmaul respirations (deep labored breathing)
4. GI: nausea/vomiting
treatment for metabolic acidosis
based on cause
if due to renal failure use sodium bicarbonate
metabolic alkalosis
bicarb greater than 26mEq/L combined with pH greater than 7.45
metabolic alkalosis process
due to either:
1. an excess in base as a result of antacid use, bicarbonate use, or use of lactate in dialysis
OR
2. acid loss from protracted vomiting, gastric suction, hypochloremia, excess diuretics, high levels of aldosterone
signs and symptoms of metabolic alkalosis
1. Neurological: dizziness, lethargy, disorientation, seizures, coma
2. Musculoskeletal: weakness, muscle twitching, muscle cramps, tetany
3. Other - Nausea, respiratory depression
treatment for metabolic alkalosis
difficult to treat. you can either stimulate kidneys to excrete bicarb with acetazolamide (diamox) or give IV acids
pH in ABG
measurement of acidity or alkalinity
based on hydrogen ions present
normal range is 7.35-7.45
PaO2 in ABG
partial pressure of oxygen dissolved in arterial blood
normal range is 80-100mmHg
SaO2 in ABG
arterial oxygen saturation
normal range is 95-100%
PaCO2 in ABG
partial pressure of carbon dioxide dissolved in arterial blood
normal range is 35-45mmHg
HCO3 in ABG
calculated value of amount of bicarbonate in blood stream
normal range is 22-26mEq/L
BE in ABG
base excess; the amount of excess or insufficient level of bicarbonate in the system
normal range is - 2 to +2mEq/L
(negative base excess means there is a deficit)
steps for determining if there is uncompensated respiratory or metabolic acidosis/alkalosis
steps for determining if there is partially compensated respiraratory or metabolic acidosis/alkalosis
steps for determining if there is fully compensated respiraratory or metabolic acidosis/alkalosis
chem 7 shorthand diagram
describe how different tissue densities appear on xray
factors that affect xray image quality
motion
scatter
magnification
distortion
the closer the pt to the film the _____ magnification and ______ distortion
the closer the pt to the film the less magnification and less distortion
what are the essential steps for evaluating a xray
R2D2: right patient, right film, done right, da normal stuff
and
ABS: aha factor, bone is smooth, soft tissue inthe normal places
be able to ID the following skeletal anatomy on xray:
xiphoid process
clavicle
scapula
manubrium
sternomanubrial angle
sternum
costal cartilages
ribs
suprasternal notch
be able to ID the following parenchyma on xray:
right and left bronchus
trachea
bronchioles
alveolar duct
alveolar sac
(may not see all but know their location)
trachea divides at sternal angle!
be able to locate the following on xray:

Upper Lobe of R Lung
Middle Lobe of R Lung
Lower Lobe of R Lung
Upper Lobe of L Lung 5-Lingula
Lower Lobe of L Lung
R Hemidiaphragm
Cardiophrenic Angle
Lateral Costophrenic Angle
1-Upper Lobe of R Lung
2-Middle Lobe of R Lung
3-Lower Lobe of R Lung
4-Upper Lobe of L Lung 5-Lingula
6-Lower Lobe of L Lung
7-R Hemidiaphragm
8-Cardiophrenic Angle
9-Lateral Costophrenic Angle
be able to ID the following

Trachea
Clavicle
R Lung
L Lung
Heart
Posterior Rib
Anterior Rib
1-Trachea 2-Clavicle
3-R Lung 4-L Lung
5-Heart 6-Posterior Rib
7-Anterior Rib
ID the following:

Area of Aortic Arch
Edge of Main Pulmonary Artery
Edge of Descending Aorta
Edge of L Atrial Appendage
Edge of L Ventricle
Edge of R Atrium
1-Area of Aortic Arch
2-Edge of Main Pulmonary Artery
3-Edge of Descending Aorta
4-Edge of L Atrial Appendage
5-Edge of L Ventricle
6-Edge of R Atrium
ID the following:
L Pulmonary Artery to Upper Lobe
Area of Carina
L Main Bronchus
R Main Bronchus
R Pulmonary Artery to Lower Lobe
Peripheral Pulmonary Vessels
1-L Pulmonary Artery to Upper Lobe
2-Area of Carina
3-L Main Bronchus
4- R Main Bronchus
5-R Pulmonary Artery to Lower Lobe
6-Peripheral Pulmonary Vessels
atelectasis
collapsed or airless condition of the lung
mediastinum
1. A septum or cavity between two principal portions of an organ.

2. The mass of organs and tissues separating the lungs. It contains the heart and its large vessels, trachea, esophagus, thymus, lymph nodes, and connective tissue.
silhouette sign
loss of normal border between structures we should see silhouettes in the following areas:

1. Upper right heart border/ascending aorta where it contacts anterior segment of RUL
2. Right heart border where it contacts right middle lobe medially
3. Upper left heart border where it contacts anterior segment of LUL
4. Left heart border where it contacts lingula anteriorly
5. Aortic knob where it contacts apical portion of LUL posteriorly
6. Anterior hemidiaphragms where they contact the lower lobes anteriorly (bilateral)
cardiomegaly with pulmonary edema
will see enlarged heart structure on xray- pulm edema will be seen
infiltrates on xray
will have fuzzy non defined edges on xray
lung mass
will have well defined morders on xray
pericardial effusion
will see enlarged cardiac sillouette, biggest differentiation from cardiomegaly is the "Fat-pad sign" from separation of retrosternal from epicardial fat line >2 mm (15%) only seen in lateral views
pleural effusion
If the patient is upright when the x-ray is taken, a pleural effusion will obscure the costophrenic angle and hemidiaphragm. If a patient is supine a pleural effusion layers along the posterior aspect of the chest cavity and becomes difficult to see on a chest x-ray.
pneumonia
can be diffuse infiltrates or consolidated, often times in lower lobes
pneumothorax
Visible pleural edge (blue line)
Lung markings not visible beyond this edge
how to question validity of a primary guide study on diagnostic testing
1. ask if there was an independent, blind comparison with a reference standard
2. ask if the patient sample included an appropriate spectrum of patients to whom the diagnostic test will be applied in clinical practice
how to question validity a secondary guide study on diagnostic testing
1. how was study conducted?
2. were methods described in such detail that you could fully replicate the study?
3. did the results of the evaluated test influence the decision to perform the reference standard?
4. were the methods for performing test described in such detail that you could replicate?
questions to ask yourself about studies on diagnostic testing
1. are the results of the study valid?
2. what were the results?
3. will the results help in the care of my patient?
4. what is the sensitivity and specificity?
5. is this the gold standard, if not how does it compare to gold standard?
6. what is the pretest probability?
7. what is the liklihood ratio?
8. what is the posttest probability?
9. what is PPV and NPV?
10. look at true positives and false positives
what things should you consider when you decide if the results will help in the care of your patients
1. Will the reproducibility of the test result and its interpretation be satisfactory in my setting?
2. Are the results applicable to my patient?
3. Will the results change my management?
4. Will patients be better off as a result of the test?
sensitivity
proportion of people who HAVE the disorder who HAVE a POSITIVE test
specificity
proportion of people who DO NOT have the disorder who have a NEGATIVE test
gold standard
best test available under reasonable conditions
pretest probability
The probability that a person has a particular disease before any test results are obtained
liklihood ratio
Ratio of positive test in people WITH the disease to positive test in people WITHOUT the disease
- indicates how much a given diagnostic test will change the pretest probability
1. If liklihood ratio = 1 then post test probability is the same as pretest
2. If liklihood ratio > 1 then testing increases likelihood disease is there
3. if liklihood ratio < 1 then testing decreases liklihood disease is there
applying liklihood ratio
1. If LR >10 or < 0.1 large and often conclusive changes from pretest to posttest
2. If LR is 5-10 or 0.1-0.2, moderate shift
3. If LR is 2-5 and 0.5-0.2, small shift but sometimes important
4. if LR is 1-2 and 0.5-1 small shift, rarely important
post test probability
can use nomogram: the probability that an individual has a disorder after the test has been applied
positive predictive value
probability of disease in patients with a positive test (true positives/all positives)
negative predictive value
probability of NO disease among patients with a negative test
when do PPV and NPV change
change depending on the population and prevalence of the disease within that population: how accurate is the test going to be within a given population
using a table to calculate sensitivity, specificity, ppv and npv
1. Sensitivity = A / (A + C)
2. Specificity = D / (B + D)
3. Positive predictive value = A / (A + B)
4. Negative predictive value = D / (C + D)
diagnostic test
test perfomred to help in diagnosis and/or detection of a disease
prognostic test
test performed to make a prediction of the course of a disease
validity
degree to which the test measures what it claims to measure
reliability
extent to which a test gives consistent results
P-value
how much evidence there is to reject the null hypothesis. Considered statistically significant if P < 0.5 or 0.1
6 steps in PFT evaluation
1. confirm demographic data
2. ask what do we know about the patient
3. ask do we have any additional lab values that tell us something about the patient? if so what do they tell us?
4. are PFT results acceptable and reproducible, if not what should we keep in mind
5. Is the pattern obstructive, restrictive or normal?
6. how severe is the defect and does it change with bronchodilator treatment?
flow volume loops to recognize:
normal, obstructive, restrictive
air trapping
refers to the abnormal retention of gas within the lung following expiration
diffusion capacity
The capacity of the alveolocapillary membrane to transfer gas.
DLCO
diffusing capacity of the lung; the capacity of the lungs to transfer carbon monoxide
DLCOc
the DLCO adjusted for hemoglobin of pt
DLVA
the DLCO adjusted for volume
DLVC
the DLCO adjusted for both volume and hemoglobin
ERV
expiratory reserve volume; the maximum volume of air that can be exhaled from the end-expiratory tidal position
FET
forced expiratory time; the amount of time the patient exhales during the FVC maneuver (in seconds)
FEV1
forced expiratory volume in first second; volume of air forcibly expired from a maximum inspiratory effort in the first second
FEV1/FVC ratio
ratio of forced expiratory volume in one second to forced vital capacity
FRC
functional residual capacity; the volume of air in the lungs following a tidal volume exhalation
= ERV + RV
FVC
forced vital capacity; the total volume that can be forcefully expired from a maximum inspiratory effort
IC
inspiratory capacity; the maximum volume of air that can be inhaled from tidal volume end expiratory level
IRV
inspiratory reserve volume; maximum volume of air that can be inhaled from the end-inspiratory tidal position
LLN
lower limit of normal; the lowest value expected for a person with normal lung function of the same age, gender, and height
PEF
peak expiratory flow; the highest forced expiratory flow, measured in L/second
RV
residual volume; volume of air that remains in the lungs after maximal exhalation
TLC
total lung capacity; the total volume of air in the lungs at full inhalation; the sum of all volume compartments
TV or VT
tidal volume; the volume of air that is inhaled or exhaled with each breath when a person is breathing at rest
VC
vital capacity; the maximum volume of air that can be exhaled starting from maximum inspiration
flow time curve or volume time curve
pseudorestriction
when FVC is decreased due to reduced airflow, air trapping, and increased residual volume
static lung volume
Static lung volumes are determined using methods in which airflow velocity does not play a role.
Residual Volume and Total Lung Capacity are static volumes and must be measured either directly by equilibration of a foreign gas such as Helium dilution or by calculation. (Dynamic is Spirometry- you are measuring the volume directly on the flowmeter)
spirometry
Measuring whether a person has obstructed, restricted, or both obstructed and restrictive pathology (pseudo restriction), by having the patient blast out air and continue to blow for 6 seconds
Explain the components of the volume-time spirogram;
The spirogram is usually used to describe the derivation of both spirometry and TLC (Total Lung Capacity)
includes FEV, IRV, TV, IC, FVC, RV, FRC, FVC, TLC
flow volume loop
be able to ID: PEFR, PVC, EC, FVC,
IC
volume time spirometrygraph
indications for PFTs
1. To evaluate symptoms and signs of lung disease
2. To assess the progression of lung disease
3. To monitor the effectiveness of therapy
4. To evaluate some preoperative patients
5. To screen people at risk for pulmonary disease
6. To monitor for potentially toxic effects of certain drugs or chemicals
what are the factors that affect diffusing capacity of the lung
1. blood issues such as anemia
2. area issues such as emphysema or pulmonary embolism
3. membrane permeability issues such as pulmonary fibrosis or excessive mucous
obstructive disease signs on PFTs
1. FEV1- decreased
2. FVC - slightly decreased or normal
3. FEV1/FVC - decrease below 70% of the predicted value
4. TLC - normal or above normal
restrictive disease signs on PFTs
1. FEV1 - decreased
2. FVC - decreased by same percentage as FEV1
3. FEV1/FVC - normal or above normal
4. TLC - less than 80% predicted
pseudorestriction disease signs on PFTs
1. FEV1 - decreased
2. FVC - decreased
3. FEV1/FVC - normal or above normal
4. TLC - greater than 80% predicted
flow chart for interpreting PFTs