Fecalysis

Question 1

True or false. The normal pH of stool ranges from 5 to 6.

Answer 1

False.

Remarks. The normal stool pH is 7 to 8. A pH of less than 5.5 is indicative of carbohydrate disorders .

Question 2

In microscopic examination of feces, how many neutrophils per hpf is indicative of intestinal invasive conditions?

Answer 2

Three per hpf

Question 3

You examined the entire slide for 5 min and see muscle fibers with striations only in one direction. How will this be reported? What is its significance?

Answer 3

It does not need to be reported.
One-directional striated muscle fibes = partly digested
Two-directional = undigested
No striations = digested
Remarks: Only undigested muscle fibers are reported. More than 10 is significant.

Question 4

Why is guaiac reagent the best for FOBT compared to benzidine and ortho-tolidine?

Answer 4

Because it has the least sensitivity in order to not overdiagnosed git bleeding.
B>O>G in order of sensitivity.

Question 5

How much fecal bleeding is considered clinically significant?

Answer 5

More than 2.5ml per 150 grams stool.

Remarks: 2.5ml or less is still normal.

Question 6

Observation of how many oil droplets/hpf is indicative of steatorrhea?

Answer 6

More than 60 oil droplet/ hpf is indicative of steatorrhea.

Question 7

For quantitative fecal analysis, what will be instructed to the patient in terms of grams of fat intake per day? And at least how many days will he/she collect?

Answer 7

100 grams of fat/day

At least a 3 day specimen is best

Question 8

In infectious diarrhea (bacterial/viral/protozoan), what is the expected osmotic gap and electrolytes of the feces?

Answer 8

Secretory diarrhea (infectious) has high fecal osm > 50osm/kg and high electrolytes versus osmotic diarrhea (steatorrhea) <50 osm/kg and low electrolytes.

Question 9

What is the best test for distinguishing between malabsorption and maldigestion? 
A. Hemoccult ICT
B. D-xylose test
C. Van de Kamer 
D. Gelatin test

Answer 9

B. D-xylose test
Remarks: D-xylose is a sugar that does not need to be digested but needs to be absorbed to be present in the urine. If urine D-xylose is low this indicates malabsorption.
Hemoccult ICT - is an immunochemical FOBT specific for human blood in feces.
Van de Kamer is the gold standard for fecal fat quantification.
Gelatin test- insensitive test that detects severe cases of panc insufficiency.

Question 10

Aside from biliary obstruction which of the following may cause a pale stool? 
A. Beets
B. Rifampin 
C. Barium sulfate
D. Raw broccoli
E. Cauliflower

Answer 10

C. Barium sulfate
Remarks: beets and rifampin can make the feces red. Raw broccoli and cauliflower can cause false negative fobt hence must be prevented for 3 days prior to fobt.

Question 11

How many samples of stool shall be collected before reporting a negative result?
A. Three samples from three different stools
B. Two samples from two different stools
C. Three samples from two different stools
D. Two samples from three different stools

Answer 11

D. Two samples from three different stools