Lab Studies

Question 1

Specificty

Answer 1

SpPIN- positive rules the disease in…no false positives

Question 2

Sensitivity

Answer 2

SnNou- negative rules the disease out…no false negatives

Question 3

Routine lab CBC include:

Answer 3

RBC (total #)
Hgb, Hct
MCV (average volume per RBC)
MCH (average Hgb per RBC.."_chromic")
MCHC (average concentration of Hgb in cell)
RDW (variation of RBC population
WBC (absolute # and differential for types)
Platelets

Question 4

Basic metabolic panel or Chem 7 components

Answer 4

Glucose, Na (dehydration)
K (hypo/hyperkalemia)
Cl (electrolyte, acid-base, H2O balance)
Bicarb (acid-base balance)
BUN (blood urea nitrogen is renally cleared)
Creatinine (more specific than BUN)
Ca

Question 5

Coagulation panel

Answer 5

aPTT (1,2,5,8,9,10,11,12) monitor heparin

PT (1,2,5,7,10) monitor coumadin

Question 6

Urinalysis

Answer 6

Macroscopic- color, turbidity
Dipstick chemical analysis- pH, specific gravity, protein, glucose, ketones, nitrite, leukocyte esterase
Microscopic- crystals, casts, squamous cells, bacteria

Question 7

urinalysis- dipstick

Answer 7

• pH 4.5-8
• sg- 1.002-1.035 lower means kidneys can’t [ ] and higher means there are big molecules present
• protein 150 mg/24 hrs or 10 mg/100 ml…detect with indicator dye bromphenol blue
• glucose- diabetes mellitus
• ketones-acetone, acetacetic acid, beta-hydroxybutyric acid result from calorie deprivation
• nitrite- gram neg rod bacteria
• leukocyte esterase- WBCs present

Question 8

urinalysis-microscopic

Answer 8

• RBC-may be swollen shrunken or dysmorphic (glomerular disease)
• WBC- (pyria) upper/lower UTI or acute glomerulonephritis, >2 abnormal…could be contaminants
• Epithelial- small # normal but nephrotic syndrome could increase numbers…squamous could be contaminants
• Casts- formed in distal tubule or collecting duct…favored by low flow rate, high Na, low pH
  - haline
  - RBC glomerulonephritis or tubular damage
  - WBC inflammation
  - granular was in nephron for some time
  - broad from damaged and dilated tubules
• bacteria- keep refridgerated, need culture
• yeast- candida
• Crystals- Ca oxalate, triple phosphate, amorphous phosphate
• Misc…sperm, crud, pinworm ova, schistosomiasis ova

Question 9

Specimen collection

Answer 9

clean catch, evaluate w/in 1 hr of collection (longer will result in decreased clarity, rise in pH, loss of ketones, cells, casts, overgrown bacteria)

Question 10

Cardiac enzymes

Answer 10

*Troponin I/T: very specific for cardiac injury, rises 2-6 hrs after injury and peaks in 12-16
*Creatinine kinase- CK-MB, CK-MM, CK-BB
rises 4-6 hrs, peaks at 24 hrs returns to normal in 3-4 days
*Myoglobin- skeletal or cardiac, rises 2 hrs after Mi, peaks 6-8 hrs, returns to normal 20-36 hrs

Question 11

Lipid panel

Answer 11

Cholesterol- most accurate after 10-12 hr fast
Triglycerides (80% VLDL, 15% LDL), 32 in men, 38 in women
LDL= total cholesterol- HDL- VLDL
VLDL= triglycerides/5
*total cholesterol 240 high

Question 12

sputum evaluation

Answer 12

• gram stain, bacterial culture, and acid-fast culture
• transudative filtrate
• Exudate contains debris and protein

Question 13

indications for types of WBCs

Answer 13

neutrophils bacterial
lympocytes viral
eosinophils allergies or parasite

Question 14

esophageal/gastric pathology

Answer 14

gastrin- produced by G cells and triggers release of gastric acid
*normal is <110 pg/ml (lowest in am)

Question 15

quantitative stool studies

Answer 15

48-72 hrs for weight quantity (>250g/24 hr is diarrhea)

fecal fat 7-14 g/ 24 hr (>14g/24 hr= disorders of fat digestion)

Question 16

stool osmolality

Answer 16

spot stool specimen, stool electrolytes (for osmotic diarrhea),

Question 17

stool laxative screen

Answer 17

magnesium, phosphate, and sulfate levels

Question 18

other stool screenings

Answer 18

• fecal leukocytes (implies underlying inflammatory disorder, ova and parasites- giardia and E. histolytica)
• occult blood

Question 19

stool culture

Answer 19

enteric pathogens

immunoassays for C.diff (bacteria), rotavirus (viral), protozoal antigens (giardia and e hystolytica)

Question 20

helicobacter pylori infections

Answer 20

• spiral urease-producing micaerophilic gram- rod
• causes gastritis, peptic ulcer disease, +/- gastric cancer
• serologic test for IgG Ab, antigen in stool
• urease breath test

Question 21

liver disease

Answer 21

enzymes
function evaluation- coagulation, protein
pathogens- viral hepatitis

Question 22

liver enzymes

Answer 22

ALT- contained in hepatocytes and release with injury or degeneration (sensitive but non-specific)
AST- contained in hepatocytes (plus others though so non-specific)
GGT- fairly non-specific
ALK-Phos- bile duct injury (also seen in bone, kidney, placenta, intestine, and lung)

Question 23

bilirubin

Answer 23

heme–>indirect/unconjugated bilirubin carried by albumin to liver–> direct/conjugated bilirubin attached to glucuronide and excreted in bile

Question 24

disorders with increased total or indirect bilirubin

Answer 24

hemolytic anemia
physiologic jaundice
sickle cell anemia
transfusion reaction
pernicious anemia
pernicious anemia
resolution of a large hematome

Question 25

increased direct bilirubin

Answer 25

bile duct obstruction cirrhosis hepatitis

Question 26

hepatitis panel

Answer 26

a-e diagnosis based on detection of Ab and Ag Acutely Infected Immune to HepB HBsAg positive negative anti-HBc positive negative antiHBs negative positive IgMantiHBs positive ---

Question 27

ammonia levels NH3

Answer 27

increased levels of hepatic encephalopathy (liver normally clears it)

Question 28

coagulation profile- liver function test

Answer 28

decreased factros 2,5,7,9,10 cause prolonged PT and aPTT decreased antithrombin III platelets <100,00 in 2/3 of pts w/ liver failure

Question 29

ascites fluid analysis

Answer 29

``` macroscopic (turbidity, color) cell count (presence of WBCs, type) cultures albumin (portal hypertension) exudate (any debris or proteins) ```

Question 30

pancreatic enzymes

Answer 30

amylase | lipase (specific to pancreas)

Question 31

renal function tests

Answer 31

* creatinine- non-protein metabolism in proportion to mm mass...depends on GFR so clearance is used to determine GFR [(140-age)xweight/ serum creat] * BUN- protein metabolism (indicates pre-renal)

Question 32

PSA

Answer 32

prostate specific antigen glycoprotein found in prostate acinar cell usually greater than 4 is worrisome for cancer

Question 33

Genitourinary

Answer 33

* serum hCG- elevated in cancer and pregnancy * STDs- assess w/ gram stain, cultures, DNA probe (herpes w/ tzanck test) * PAP smear- HPV, assess estrogen effect

Question 34

endocrine- how does the interaction of multiple glands control release of hormone? - thyroid - parathyroid - diabetes

Answer 34

* hypofunction- stimulatory test, hyper- suppresssion * thyroid- pituitary releases TSH-->thyroid releases T3 and T4 (synthroid)--> levels negative feedback * parathyroid- PTH released when Ca is low * Diabetes mellitus- fasting blood sugar 2 hr oral glucose tolerance test for gestational diabetes, use glycosylated Hgb

Question 35

endocrine | adrenal-pituitary function

Answer 35

* ACTH stimulation test...it stimulates adrenal gland to produce cortisol. * Dexamethasone suppression of pituitary ACTH secretion..r/o cushing's * aldosterone

Question 36

endocrine | gonadal function

Answer 36

``` chromosome analysis estrogen in serum FSH and LH progesterone testosterone (semen) ```

Question 37

endocrine | GH, somatomedin C, prolactin

Answer 37

GH- GHRH from hypothalamus IGF-1- mediates growth promoting effects of GH prolactin- most common pituitary tumor, causes gynecomastia

Question 38

hematology RBC bone marrow Coombs test

Answer 38

*RBCs if concerned about anemias, assess contents and shape *bone marrow looking for abnormal cells, usually from iliac crest *Coombs test- direct- RBCs w/premade Abs indirect- serum +standardized RBC

Question 39

``` hematology EPO ferritin haptoglobin TIBC serum iron ```

Answer 39

*from kidneys to maintain appropriate hgb, differential diagnosis for anemia *correlates with total body iron stores *binds free hgb..decreased in hemolytic anemia *concentration of transferrin..rises in iron deficiency *serum iron- variation though so poor test IRON DEFICIENCY= low serum iron and ferritin, high TIBC