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18 Cards in this Set
- Front
- Back
What is the most representative way to collect fecal specimens for quantitative analysis? |
3-day collection in cans (resembline paint cans) |
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What types of analysis are included in a routine fecal screening test? |
color, consistency, WBC's, muscle fibers, fecal fat, and occult blood |
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What is the clinical significance of black, tarry stool? |
associated with upper gastrointestinal bleeding |
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What causes the black color? |
blood that originates from the esophagus, stomach, or duodenum; this blood takes about three days to appear in the stool; during this time, degradation of hemoglobin produces the characteristic black color and tarry consistency of stool |
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What are the 3 clinical problems associated with pale-colored stool? |
obstruction of the flow of bile pigment to the intestines
lack of enzymes necessary for the digestion and absorption of fat
recent administration of barium |
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due to fat malabsorption (fatty stools); the stool will be bulky and frothy and may appear pale brown or dark yellow |
steatorrhea |
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What will the feces look like in a patient with diarrhea? With constipation? An obstruction? |
water stool
small, hard stools
slender, ribbon-like stools |
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What is the clinical significance of neutrophils in feces? |
conditions that affect the intestinal wall (like ulcerative colitis) and infection the invasive bacterial pathogens; bacteria that cause diarrhea by toxin production, viruses, and parasites usually do not cause the appearance of neutrophils in the feces; three neutrophils per hpf can be indicative of an invasive condition |
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How are stools tested for neutrophils? |
wet preps stained with methylene blue, Gram Stain, or Wright's Stain |
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How are stools tested for qualitative fecal fat? Neutral fats? |
microscopic examination of stained fats
staining a stool sample with Sudan III, Sudan IV, or Oil REd O. Look for large, orange-red droplets, most often located near the edge of the coverslip. Greater than 60 droplets per hpf is increased. |
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Why must a second slide be examined after staining for neutral fats? |
because soaps and fatty acids in the specimen will not stain directly with Sudan III, so the specimen must be mixed with acetic acid and heated and examined once more for Sudan III stained droplets |
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Why do we look for meat fibers in feces? |
the presence of undigested striated muscle fibers can aid in the diagnosis of a patient with pancreatic undufficiency (cystic fibrosis), and in a patients with biliary obstruction and gastrocolic fistulas |
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Why is the occult blood one of the most important tets performed on feces? |
early detection of colorectal cancer |
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What is the reagent used to detect occult blood in feces? (Explain the reagents and procedure.) |
Guaiac reagent detects blood in the following manner: the pseudo-peroxidase activity of hemogloin reacts with hydrogen peroxide to oxidize a colorless compound (guaiac) to a colored (blue) compound |
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What is the method used routinely for quantitative fecal fat measurement? Explain it. |
The Van de Kamer titration
Fecal lipids are converte3d to fatty acids and titrated to a neutral end-point with sodium hydroxide. Fat content is reported as grams of fat - or fatty acids - per 24 hours |
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What is the APT and its clinical significance? |
used to distinguish fetal blood from swallowed maternal blood in an infant's stool or vomitus |
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How and why do we test for trypsin in feces? |
by placing a small amount of stool emulsified in water on a piece of x-ray paper
In the presence of trypsin, the gelatin on the x-ray paper will be digested, leaving a clear area on the paper |
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What is the clinical significance of trypsin in feces? |
decreased trypsin production is associated with pancreatic insufficiency |