Which stool test is most helpful for detecting fat malabsorption in suspected intestinal fat malabsorption?

• A. Stool for leukocytes
• B. Stool for 72-hour fecal fat
• C. Stool for ova and parasites
• D. Stool for culture and sensitivity

Answer: (B)

Fat malabsorption shows up as fat being lost in stool, so the most informative test is a quantitative 72-hour stool fat collection. By asking the patient to eat a diet with a normal fat intake and then collecting all stool for three days, you directly measure how much fat is being excreted. If the fat excretion exceeds the normal range (roughly more than about 7 g per day on a standard fat intake), it indicates steatorrhea and fat malabsorption. This direct measurement is more sensitive and specific for detecting fat loss than tests that look for infection or inflammation.

Stool leukocytes detect inflammatory or infectious processes, not fat absorption. Stool ova and parasites screens for parasitic infections, which may cause diarrhea but don’t quantify fat malabsorption. Stool culture and sensitivity looks for bacterial infections, again not fat absorption. The 72-hour fecal fat test remains the best choice because it specifically quantifies fat Malabsorption rather than inferring it from other findings.