AUBF MTAP (Fecalysis)

100-200g

Approximately how many grams of feces are excreted in a 24-hour period?

Small intestine

It is the primary site for the final breakdown and reabsorption of digestive contents

• Trypsin

• Chymotrypsin

• Amino peptidase

• Lipase

Digestive enzymes secreted into the small intestine by the pancreas include:

Bile salts

Provided by the liver and aids in digestion of fats

Water and electrolytes

These are readily absorbed in both the small and large intestines

Large intestine

It is capable of absorbing approximately 3,000 mL of water

Diarrhea

It is defined as an increase in daily stool weight above 200 g, increased liquidity of stools, and frequency of more than three times per day

Measuring fecal electrolytes and the osmotic gap

Watery diarrhea is divided into secretory or osmotic types by:

30 mmol/L

Normal fecal sodium is:

75 mmol/L

Fecal potassium is:

Malabsorption of sugars

A fecal fluid pH of less than 5.6 indicates:

• Disaccharidase deficiency (lactose intolerance)

• Malabsorption (celiac sprue)

• Poorly absorbed sugars (lactose, sorbitol, mannitol)

• Laxatives

• Magnesium-containing antacids

• Amebiasis

• Antibiotic administration

Causes of osmotic diarrhea include:

Irritable bowel syndrome (IBS)

It is a functional disorder in which the nerves and muscles of the bowel are extra sensitive

Intestinal hypermotility

The excessive movement of intestinal contents through the GI tract that can cause diarrhea because normal absorption of intestinal contents and nutrients cannot occur

RGE

• Describes hypermotility of the stomach and the shortened gastric emptying half-time, which causes the small intestine to fill too quickly with undigested food from the stomach

• Hallmark of EDS

35-100 minutes

Healthy people have a gastric emptying half-time range of:

<35 minutes

People with RGE have a gastric emptying time of:

Late dumping

Type of RGE that occurs 2 to 3 hours after a meal and is characterized by weakness, sweating, and dizziness.

Hypoglycemia

It is often a complication of dumping syndrome

Steatorrhea

Useful in diagnosing pancreatic insufficiency and small bowel disorders that cause malabsorption

Malabsorption

A low D-xylose test indicates:

Pancreatitis

A normal D-Xylose test indicates:

Small intestine

In what part of the digestive tract do pancreatic enzymes and bile salts contribute to digestion?

Large intestine

Where does the reabsorption of water take place in the primary digestive process?

Fecal neutrophils

Which of the following tests is not performed to detect osmotic diarrhea?

Blood

The normal composition of feces includes all of the following except:

Quantitative fecal fat testing

What is the fecal test that requires a 3-day specimen?

Urobilin

The normal brown color of the feces is produced by:

Increased reabsorption of intestinal water and electrolytes

Diarrhea can result from all of the following except:

Fat

Stools from people with steatorrhea will contain excess amounts of:

Yellow-green: barium sulfate

Which of the following pairings of stool appearance and cause do not match?

Intestinal constriction

Stool specimens that appear ribbon-like are indicative of which condition?

Upper GI bleeding

A black tarry stool is indicative of:

Pilocarpine iontophoresis

Chemical screening tests performed on feces include all of the following, except:

Vibrio cholerae

Secretory diarrhea is caused by:

Osmotic diarrhea

The fecal osmotic gap is elevated in which disorder?

Neutrophils are present in conditions that affect the intestinal wall

Microscopic examination of stools provides preliminary information as to the cause of diarrhea because:

FALSE

TRUE OR FALSE

The presence of fecal neutrophils would be expected with diarrhea caused by a rotavirus

Neutral fats

Large orange-red droplets seen on direct microscopic examination of stools mixed with Sudan III represent:

Fatty acids, soaps, and neutral fats

Microscopic examination of stools mixed with Sudan III and glacial acetic acid and then heated will show small orange-red droplets that represent:

Have two-dimensional striations

When performing a microscopic stool examination for muscle fibers, the structures that should be counted:

Steatorrhea

A value of 85% fat retention would indicate:

Fecal occult blood

Which of the following tests would not be indicative of steatorrhea?

Is not visibly apparent in the stool specimen

The term “occult” blood describes blood that:

Two samples taken from different parts of three stool specimens

What is the recommended number of specimens that should be tested to confirm a negative occult blood result?

Test for human globulin

The immunochemical tests for occult blood:

Pseudoperoxidase activity of hemoglobin

Guaiac tests for detecting occult blood rely on the:

Fetal hemoglobin is present

What is the significance of an APT test that remains pink after the addition of sodium hydroxide?

Converted to fatty acids before titrating with sodium hydroxide

In the Van de Kamer method for quantitative fecal fat determinations, fecal lipids are:

Cystic fibrosis

A patient whose stool exhibits increased fats, undigested muscle fibers, and the inability to digest gelatin may have:

Positive Clinitest

A stool specimen collected from an infant with diarrhea has a pH of 5.0. This result correlates with a:

D-Xylose test

Which of the following tests differentiates a malabsorption cause from a maldigestion cause in steatorrhea?

Intestinal oxidation of stercobilinogen to urobilin

The brown color of the feces results from:

Mucus-coated

Type of stool that may be caused by pathological colitis, Crohn disease, colon tumors, or excessive straining during elimination

Lactoferrin latex agglutination

This test is used for detecting fecal leukocytes and remains sensitive in refrigerated and frozen specimens

Lactoferrin

A component of granulocyte secondary granules which indicates an invasive bacterial pathogen

Soaps and fatty acids

Which do not stain directly with Sudan III?

gFOBT

Screening test used most frequently for fecal blood

Decreased

To prevent false-positive reactions in gFOBT, test sensitivity must be:

Blue

What color is the filter paper when pseudoperoxidase activity is present?

iFOBT

PRINCIPLE: Specific for the globin portion of human hemoglobin and uses polyclonal anti human hemoglobin antibodies

• More sensitive to lower GI bleeding

HemoQuant

It offers a porphyrin-based FOBT fluorometric test for hemoglobin based on the conversion of heme to fluorescent porphyrins

Van de Kamer

• Routinely for fecal fat measurement

• Gold standard for fecal fat

1H NMR

• Rapid (5 minutes) and safe procedure for analyzing quantitative fecal fat

• In this method, the homogenized specimen is microwaved, dried and analyzed.

• Correlates well with the gravimetric method, and it is widely used in reference laboratories.

Acid Steatocrit

• It is a rapid test to estimate the amount of fat excretion

• Used to screen steatorrhea in pediatric populations

NIRS

• A rapid procedure for fecal fat that requires less stool handling by laboratory personnel

• The test requires a 48- to 72-hour stool collection to exclude day-to-day variability

Yellow-brown

In APT test, denaturation of the maternal hemoglobin (HbA) produces a what color of supernatant after standing for 2 minutes?

Chymotrypsin

Which enzyme is capable of gelatin hydrolysis but is measured most frequently by spectrophotometric methods?

Elastase I

• An isoenzyme of the enzyme elastase and is the enzyme form produced by the pancreas

• Present in high concentrations in pancreatic secretions and is strongly resistant to degradation

ELISA

Elastase I is measured by:

Osmotic diarrhea

The presence of increased carbohydrates in the stool produces what type of diarrhea?

7 and 8

Normal stool pH is between:

0.5 g/dL

It is considered indicative of carbohydrate intolerance

Sucrose

Which sugar is not detected by Clinitest?