Chapter 15 - Fecal Analysis

RGE

RGE

________ can be divided into early dumping and late dumping depending upon how soon after a meal the symptoms occur.

Pseudoperoxidase activity

________ is present from hemoglobin and myoglobin in ingested meat and fish, certain vegetables and fruits, and some intestinal bacteria, so the sensitivity of the test must be decreased.

Stool chromatography

________ to identify the malabsorbed carbohydrate is available but rarely necessary for the diagnosis of sugar intolerance.

Hypoglycemia

________ is often a complication of dumping syndrome.

Lipids

________ included in the microscopic examination of feces are neutral fats (triglycerides), fatty acid salts (soaps), fatty acids, and cholesterol.

Oral antibiotics

________ (oxidation of fecal bilirubin to biliverdin), green vegetables or food coloring.

Wrights

Dried preparations stained with either ________ or Gram stains provide permanent slides for evaluation.

Sucrose

________ is not detected by the Clinitest method because it is not a reducing sugar.

abnormal excretion

The Clinitest on stools can distinguish between diarrhea caused by ________ of reducing sugars and those caused by various viruses and parasites.

premature infants

In ________ there is correlation between a positive Clinitest and inflammatory necrotizing entercolitis.

Elastase I

________ is present in high concentrations in pancreatic secretions and is strongly resistant to degradation.

Specimens

________ can be examined as wet preparations stained with methylene blue or as dried smears stained with Wrights or Gram stain.

neutrophils

Leukocytes, primarily ________, are seen if the intestinal mucosa is affected.

Soaps

________ and fatty acids do not stain directly with Sudan III; therefore, a second slide must be examined after the specimen has been mixed with acetic acid and heated.

motility disorders

It is not affected by ________ or mucosal defects.

Cholesterol

________ is stained by Sudan III after heating and as the specimen cools forms crystals that can be identified microscopically.

length

The ________ of the fat and solid layers are measured using a magnifying lens.

capillary tube

The ________ is centrifuged horizontally at 13, 000 rpm for 15 minutes in a microhematocrit centrifuge.

Staphylococcus aureus

________ and Vibrio spp., viruses, and parasites usually do not cause the appearance of fecal leukocytes.

Chymotrypsin

________ is capable of gelatin hydrolysis but is most frequently measured by spectrophotometric methods.

acid steatocrit

A(n) ________ of <10 % is indicative of steatorrhea in children.

Steatorrhea

________ may be present in both maldigestion and malabsorption conditions and can be distinguished by the D- xylose test.

large intestines

Water and electrolytes are readily absorbed in both the small and ________, resulting in a fecal electrolyte content that is similar to that of plasma.

Hemoglobin

________ from upper GI bleeding is degraded by bacterial and digestive enzymes before reaching the large intestine and is immunochemically nonreactive.

Random

________ specimens suitable for qualitative testing are usually collected in plastic or glass containers with screw- capped tops similar to those used for urine specimens.

Healthy individuals

________ have a gastric emptying half- time range of 35 to 100 minutes, which varies with age and gender; in this case, the time is less than 35 minutes.

oil immersion

Using ________, the finding of any neutrophils has approximately 70 % sensitivity for the presence of invasive bacteria.

bacterial degradation

Refrigerating the specimen prevents any ________.

active solids

Alterations in the motor functions of the stomach result in the accumulation of large amounts of osmotically ________ and liquids to be transported into the small intestine.

Fecal elastase I

________ is pancreas specific and its concentration is about five times higher than in pancreatic juice.

Carbohydrates

________ resistant to digestion and lactose (for those with intolerance) passes through the upper intestine and are metabolized by bacteria in the lower intestine, producing large amounts of flatus.

false positives

It does not detect bleeding from other sources such as a bleeding ulcer, decreasing the chance for ________.

ELISA test

The ________ uses monoclonal antibodies against human pancreatic elastase- 1; therefore, the result is specific for human enzyme and not affected by pancreatic enzyme replacement therapy.

proteolytic activity of bacteria enzymes

The ________ may produce false- positive results in old specimens.

Digestive enzymes

________ secreted into the small intestine by the include trypsin, chymotrypsin, amino peptidase and lipase by the pancreas, and bile salts by the liver.

Diarrhea

________ is defined as an increase in daily stool weight above 200 g with increased liquidity and frequency of more than three times per day.

Slides

________ for muscle fiber detection are prepared by emulsifying a small amount of stool in 10 % alcoholic eosin, which enhances the muscle fiber striations.

Analysis of the feces

________ focuses primarily on the proteolytic enzymes trypsin, chymotrypsin, and elastase I.

Carbohydrate malabsorption

________ or intolerance (maldigestion) is primarily analyzed by serum and urine tests; however, an increased concentration of carbohydrate can be detected by performing a copper reduction test on the fecal specimen.

Fecal lipids

________ are converted to fatty acids and titrated to a neutral endpoint with sodium hydroxide.

GI

It is more sensitive to lower ________ bleeding that could be an indicator of colon cancer or other gastrointestinal disease and can be used for patients who are taking aspirin and other anti- inflammatory medications.

Fecal chymotrypsin

________ is more resistant to intestinal degradation and is a more sensitive indicator of less severe cases of pancreatic insufficiency.

copper reduction test

The ________ is performed using a Clinitest tablet and one part stool emulsified in two parts water.

lactoferrin latex agglutination test

A(n) ________ is available for the detection of fecal leukocytes and remains sensitive in refrigerated and frozen specimens.

immunochemical fecal occult blood test

The ________ (iFOBT), is specific for the globin portion of human hemoglobin and uses anti- human hemoglobin antibodies, so it does not require dietary or drug restrictions.

fecal reducing

Testing for ________ substances detects congenital disaccharidase deficiencies as well as enzyme deficiencies due to nonspecific mucosal injury.

D xylose

________ is a sugar that does not need to be digested but does need to be absorbed to be present in the urine.

absence of bile

It is an an increase in stool fat> (6 g per day) caused by the ________ salts that assist pancreatic lipase in the breakdown and subsequent reabsorption of triglycerides.

visible striations

Digested fibers have no ________.

Rapid gastric emptying

________ (RGE) dumping syndrome 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.

Diarrhea classification can be based on four factors

duration of the illness, mechanism, severity, and stool characteristics

Osmotic gap = 290

[2 (fecal sodium + fecal potassium)]

fecal fat for adults in grams per 24 hours = [0.45 x (acid steatocrit in percent as a whole number)]

0.43

fecal fat for children up to the age of 15 years in grams per 24 hours = [0.1939 x (acid steatocrit in percent as a whole number)]

0 .2174

bacteria metabolizing food

What causes flatus?

in plastic or glass containers with screw-capped tops

What specimens are needed for qualitative testing?

3-day specimen, collected in paint cans

What specimens are needed for quantitive testing?

blockage of the bile duct, barium sulfate

What causes pale yellow, white or gray stool?

damage to the intestinal walls, possibly caused by bacterial or amebic dysentery or malignancy

What causes blood-streaked mucus-coated stool?

biliary obstruction and gastrocolic fistulas

What do the presence of increased striated muscle fibers indicative of?

60 droplets/HPF and 100 droplets/HPF, respectively

How many neutral fats and fatty acids indicate steatorrhea?

occult blood

If colorectal cancer is suspected, what test is recommended?

quantitative fat testing

What is the confirmatory test for steatorhhea?

it digests the gelatin, leaving a clear area

What does trypsin do to x-ray paper?

it becomes 5.5 due to increased lactic acid prod from bacteria

How does stool pH change in cases of intestinal disorders, and why?