Urinalysis and Body Fluids 6th Edition by Majorie DiLorenzo, Susan Strasinger

Exercise 37

Briefly describe a chemical screening test performed on feces for each of the following: fetal hemoglobin, pancreatic insufficiency, and carbohydrate intolerance.

Step 1 of 3

Chemical screening test on feces to detect fetal hemoglobin:

• APT(Alkali denaturation test) test detects the fetal hemoglobin

• APT test is usually used to discriminate maternal blood from fetal blood in the infants stool

• The test is performed by emulsifying the feces with the water to separate the hemoglobin (Hb) then in the supernatant with pink hemoglobin, 1% of sodium hydroxide added after centrifugation

o The solutions remains pink when the fetal hemoglobin (HbF) is present, which is alkali-resistant

o A yellow-brown color supernatant is formed after 2 minutes when maternal hemoglobin is present due to HbA (maternal hemoglobin) denaturation

• The specimen of stool must be tested when fresh.