Patient Assessment II: GI labs

Why do we do stool testing

Colorectal cancer screening

GI disorders (inflammation, infection)

Three FDA approved tests for colorectal cancer screening

• Guaiac FOBT (gFOBT)

• Fecal immunochemical test (FIT)

• Multitargeted stool DNA testing (FIT-DNA)

Looks for blood and abnormal DNA markers, and is approximately 92% accurate at detecting colorectal cancer

Cologuard

What can you test for when looking for inflammation and infection?

Fecal calprotectin

fecal alastase

parasites

ova & Parasite

c. diff

stool culutre

FOBT

fecal leukocytes

poultry, eggs, milk products, fresh produce, meats, contact with pets/animals (reptiles)

Salmonella

fecal-oral, therefore found in many foods

Shigella

poultry, water-borne outbreaks, direct contact with

animals or animal products

Campylobacter

Waterborne (fresh water) and foodborne (raw or undercooked); daycare (fecal-oral route); international travel

Giardia

Fecal contamination of water (drinking or swimming) or food source; can be person-to-person

Crytosporidum

Shiga-toxin producing strains (especially O157:H7)

E coli

What are the three organisms included in standard stool culture?

salmonella

shigella

camylobacter

USPSTF recommends FOBT annually in a person ages ____ with average colorectal cancer risk

50-75

USPSTF does not recommend only using ___ DNA testing as screening for colorectal cancer

fecal

3 methods for cancer screening?

Cologuard (at home)

Heme-occult stool test (in office) Stool study (in lab)

What color is postive for heme occult

blue

Immunochemical test can miss ____ bleed - globin will be digested by the time it gets in the stool

upper GI

What are the interfering factors for GI test

red meat, plant oxidizers, vit c

immunochemical test

exercise

bleeding gums or nose

medications

What is an indication for stool study with diarrhea?

> 7 days and/or > 6 unformed stools in < 24 hours

What symptoms are indications for stool studies

Diarrhea

abd pain

hematochezia

hematemesis

anemia

What are risk factors that would indicate stool studies

• Recent travel

• Exposure (healthcare workers, food handlers, farmers)

• Immune compromised, pregnancy

• Age>70

c diff severity can vary from ____ to _____

mild diarrhea; colitis/perforation

- About 1 in 6 patients who get C. diff will get it again in the subsequent ___ weeks

2-8

When should you consider C diff

- recent hospital or SNF

-3-5 abx stay

-immunosuppressed

What abx would put someone at higher risk of C diff

Clindamycin, Cephalosporins, Penicillins, Fluoroquinolones, and Amoxicillin/clavulanate

What are included on CMP that are not on BMP

liver function tests

What are liver enzymes that show levels of injury

AST ALT alkaline phosphate, bilirubin

hepatocellular function (synthesis) tests

PT albumin, bilirubin

____ is more specific to the liver

ALT

limited breakdown of waste products into urea

Ammonia

chronic liver dz leads to _______ aminotransferases where as acute injury/tox leads to _____ aminotransferases

slightly elevated or normal; extremely elevated

An enzyme that transports metabolites across cell membranes.

• Liver and bone diseases are the most common causes of pathological elevation of___level

ALP (alk phos)

The third trimester of pregnancy (placenta origin) and adolescence (bone origin) are associated with an isolated increase in serum ___ level

ALP

Hepatic ALP is present on the surface of______epithelia

bile duct

ALP half life is ____. This causes ALP to rise ____ and decrease ____

one week; late; slowly

• the product of hemoglobin catabolism

Bilirubin

heme breakdown determines the formation of ___bilirubin,

which is then transported to the liver.

unconjugated

in the liver, UDP-glucuronyltransferase conjugates the water-insoluble unconjugated bilirubin to glucuronic acid, and___ bilirubin is then excreted into the bile.

conjugated

what are some causes of unconjugated hyperbilirubinemia

hemolysis

gilberts

hematoma reabsorption

ineffective erythropoesis

what are some causes of conjugated hyperbilirubinemia

bile duct obstruction

hepatitis

cirrhosis

autoimmune cholestatic diseases

total parental nutrition

drug toxins

vanishing bile duct

produced by hepatocytes

Albumin

______ depends on the activity of clotting factors I, II, V, VII and X, which are produced in the liver.

prothrombin time

These monitor progression of liver disease

Albumin and PT

prothrombin time may be prolonged by ___ treatment, deficiency in vitamin K

warfarin

amylase and lipase are digestive enzymes released from the _____

pancreas

elevated lipase can help determine ______, ______, ____

pancreatic injury/inflammation, bowel obstruction, IBD

Hyperammonemia

90% of cases - _____

10% of cases- ______

Cirrhosis

Kidney failure, GI bleed etc

brain disorder due to a liver disorder secondary to toxins (hyperammonemia)

Hepatic encephalopathy

ALT, AST > Alk Phos ---> _____

hepatocellular d/o

Alk phos > ALT, AST ---> _____

cholestatic

AST:ALT > 2:1 ---> _____

alcoholic liver disease

inc bili with all others normal --->

isolated hyperbilirubinemia

ALT, AST > 15x ULN ----> ______

acute hepatitis

moderately inc ALT, AST ----> _____

chronic liver problem

what causes gastritis, PUD*, gastric carcinoma and MALT

H pylori

When do you test for H pylori

People with active gastric or duodenal ulcers or a history of ulcers should be tested

Testing for and treating H. pylori infection is also recommended after surgery for early gastric cancer or low-grade gastric ___ lymphoma.

MALT

How do we test for H pylori?

Urea breath test (~90% sen, 95-100% spec)

stool antigen

endoscopy and biopsy (100% sensitive and specific)

what interferes with testing of H pylori?

Recent PPI use

bismuth

abx

active PUD disease

• Immune-mediated; genetic predisposition

• Small bowel disorder - mucosal inflammation, villous atrophy, crypt hyperplasia (when exposed to gluten)

Celiac disease

ideally all testing is done while patient is on a __diet

gluten-containing

How to diagnose low risk celiac?

Serologic testing, if positive result, EGD with small bowel biopsy

How to diagnose high risk celiac

Serologic testing and EGD with small bowel biopsy

GOld standard serologic testing for celiac

Tissue transglutaminase and IgA antibody (tTG-IgA)

if you dont have enough ____ you have lactose intolerance

lactase

What symptoms does lactose intolerance cause

flatulence, bloating, cramping, diarrhea

What are the testing indications for lactose intoleracne

persistent symptoms of diarrhea, bloating, flatulence, nausea

what are the tests you can do for lactose intolerance?

Breath

Serum - no longer used

what does breath test for lactose intolerance measure?

hydrogen ions

Lactose intolerance is most often determined by elimination of ___

and evaluation of symptoms

lactose