Fecal Fat - Triglycerides Test

Triglycerides are the main form of dietary fat, made up of three fatty acids bound to a glycerol backbone. In healthy digestion, triglycerides are broken down in the small intestine by pancreatic lipase into free fatty acids and monoglycerides, which are then absorbed into the bloodstream. Because this process is usually highly efficient, only a small amount of triglycerides, or fat in any form, should appear in stool.

When fat digestion or absorption is impaired, unabsorbed lipids accumulate in the stool, a condition known as steatorrhea. However, most of the fat detected in stool is not triglyceride. By the time food reaches the colon, triglycerides have been largely hydrolyzed, leaving mainly free fatty acids, soaps (fatty acids bound to calcium or magnesium), cholesterol, and phospholipids. The presence of intact triglycerides in stool therefore usually signals severe pancreatic enzyme deficiency or very rapid intestinal transit that limits fat breakdown.