Stool Studies and Other Labs

what are the contents of stool?

bile, mucus, epithelial cells, bacteria, inorganic salts

what test requires stool sample to be refrigerated?

clostridial toxin assay (c diff)

indicated on patients with diarrhea on antibiotics with foul-smelling diarrhea

clostridial toxin assay

fastest assay for c diff

toxin B gene

measures fat content of stool

fecal fat

indicated when patient has large greasy foul stools (steatorrhea)

fecal fat test

diet for fecal fat test

100g fat/day

indicated when patients with unrelenting diarrhea fever and abdominal bloating

stool culture

t/f ova and parasites are part of normal intestinal flora

false

if this bug is found in stool, suspect PUD or gastritis

H. pylori (urea breath test)

tape test assesses presence of __________

pinworm

presents with itching in peri-anal area

pinworms

tests for hidden blood in the stool

guaiac (occult blood)

ingestion of red meat, vegetables, drugs (NSAIDS) can interfere with

guiaic

alternative to guaiac test

fecal immunochemical test

does guaiac or fecal immuochemical require diet modifications?

guaiac

determines cause of cushing syndrome or addisons disease

ATCH test

very high acth indicates __________ production in cushings syndrome

ectopic (lung, pancreas, thymus)

high ACTH indicates _______ adrenal gland failure

primary

potent glucocorticoid from the adrenal cortex stimulating gluconeogenesis

cortisol

cortisol impairs ____ secretion

insulin

low ACTH and high cortisol reveals

adrenal tumor

high ACTH and low cortisol reveals

addison's disease

low acth and low cortisol reveals

hypopituitarism

assess this if calcium levels are disrupted

PTH

pth is routinely monitored in patients with _________ failure

renal

decreased PTH is associated with

increased calcium (bone cancer, sarcoidosis, excess vitamin D, surgical ablation)

product of purine catabolism excreted by kidney

uric acid

glycoprotein found in prostatic lumen

PSA (not routinely recommended anymore)

diagnostic grey zone associated with PSA

BPH and prostatitis can both elevate PSA (4-10 ng/mL)

nonspecific test to detect illnesses associated with acute and chronic infection, inflammation, necrosis

erythrocyte sedimentation rate (ESR)

rate at which RBCs settle in saline solution

ESR (mm/hr)

as disease worsens, ESR ____________

increases

what test can be ordered to assist ESR interpretation?

c reactive protein

more sensitive for inflammation than ESR

c-reactive protein

low elevation in CRP is seen with

inflammation

high elevation in CRP is seen with

infection

antibodies associated with EBV

mono spot (best early on)

VCA-IgM (4-6 weeks)

VCA-IgG (present for life)

EA-D (3-6 months)

EBNA-IgG (present for life)

does elevated IgG mean a patient currently has Mono?

no; they have had in sometime in their life