Lab Studies Flashcards
Specificty
SpPIN- positive rules the disease in…no false positives
Sensitivity
SnNou- negative rules the disease out…no false negatives
Routine lab CBC include:
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
Basic metabolic panel or Chem 7 components
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
Coagulation panel
aPTT (1,2,5,8,9,10,11,12) monitor heparin
PT (1,2,5,7,10) monitor coumadin
Urinalysis
Macroscopic- color, turbidity
Dipstick chemical analysis- pH, specific gravity, protein, glucose, ketones, nitrite, leukocyte esterase
Microscopic- crystals, casts, squamous cells, bacteria
urinalysis- dipstick
- 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
urinalysis-microscopic
- 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
Specimen collection
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)
Cardiac enzymes
*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
Lipid panel
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
sputum evaluation
- gram stain, bacterial culture, and acid-fast culture
- transudative filtrate
- Exudate contains debris and protein
indications for types of WBCs
neutrophils bacterial
lympocytes viral
eosinophils allergies or parasite
esophageal/gastric pathology
gastrin- produced by G cells and triggers release of gastric acid
*normal is <110 pg/ml (lowest in am)
quantitative stool studies
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)
stool osmolality
spot stool specimen, stool electrolytes (for osmotic diarrhea),
stool laxative screen
magnesium, phosphate, and sulfate levels
other stool screenings
- fecal leukocytes (implies underlying inflammatory disorder, ova and parasites- giardia and E. histolytica)
- occult blood
stool culture
enteric pathogens
immunoassays for C.diff (bacteria), rotavirus (viral), protozoal antigens (giardia and e hystolytica)
helicobacter pylori infections
- spiral urease-producing micaerophilic gram- rod
- causes gastritis, peptic ulcer disease, +/- gastric cancer
- serologic test for IgG Ab, antigen in stool
- urease breath test
liver disease
enzymes
function evaluation- coagulation, protein
pathogens- viral hepatitis
liver enzymes
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)
bilirubin
heme–>indirect/unconjugated bilirubin carried by albumin to liver–> direct/conjugated bilirubin attached to glucuronide and excreted in bile
disorders with increased total or indirect bilirubin
hemolytic anemia physiologic jaundice sickle cell anemia transfusion reaction pernicious anemia pernicious anemia resolution of a large hematome
increased direct bilirubin
bile duct obstruction
cirrhosis
hepatitis
hepatitis panel
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 —
ammonia levels NH3
increased levels of hepatic encephalopathy (liver normally clears it)
coagulation profile- liver function test
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
ascites fluid analysis
macroscopic (turbidity, color) cell count (presence of WBCs, type) cultures albumin (portal hypertension) exudate (any debris or proteins)
pancreatic enzymes
amylase
lipase (specific to pancreas)
renal function tests
- 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)
PSA
prostate specific antigen
glycoprotein found in prostate acinar cell
usually greater than 4 is worrisome for cancer
Genitourinary
- 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
endocrine- how does the interaction of multiple glands control release of hormone?
- thyroid
- parathyroid
- diabetes
- 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
endocrine
adrenal-pituitary function
- ACTH stimulation test…it stimulates adrenal gland to produce cortisol.
- Dexamethasone suppression of pituitary ACTH secretion..r/o cushing’s
- aldosterone
endocrine
gonadal function
chromosome analysis estrogen in serum FSH and LH progesterone testosterone (semen)
endocrine
GH, somatomedin C, prolactin
GH- GHRH from hypothalamus
IGF-1- mediates growth promoting effects of GH
prolactin- most common pituitary tumor, causes gynecomastia
hematology
RBC
bone marrow
Coombs test
*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
hematology EPO ferritin haptoglobin TIBC serum iron
*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
