Fat Globules

General Information

Patients in whom there is a clinical suspicion of steatorrhoea should first have the diagnosis confirmed by stool testing for fat. If confirmed, a thorough history and physical examination should identify those with possible pancreatic disease or intestinal disease that can cause steatorrhoea. Subsequent blood and stool tests can then narrow the differential diagnosis and guide further investigations.

Although fatty stools have a characteristic appearance, objective confirmation of excess faecal fat should be undertaken. As fat malabsorption depends on an adequate dietary fat intake, patients who restrict the lipid composition of their diet, or are fasting, will not experience steatorrhoea, regardless of the cause. It is thus important that patients undergoing tests for faecal fat consume approximately 100 g of fat a day to ensure adequate assessment of lipid absorption.

The method utilized by this test is a Sudan stain of a random sample of homogenised stool. Acetic acid and Sudan III stain are added to the stool sample, which is then heated and placed on a glass slide. The number and size of the fat globules per high-power field (hpf) is scored.

Steatocrit and the 72-hour fat chemical analysis (van de Kamer method) are no longer routinely performed.