What test is used to evaluate fat malabsorption in stools?

The Sudan stain for fecal fat is the test used to evaluate fat malabsorption in stools because it specifically detects unabsorbed fat in feces. When fat malabsorption occurs, the body is unable to properly absorb dietary fats, leading to an increase in the quantity of fat in the stool. The Sudan stain is a special staining technique that colors fats, allowing for visual quantification of fat in the stool sample under a microscope.

In contrast, the D-Xylose absorption test is used to evaluate the absorption of simple sugars and is not specific to fat malabsorption. Stool cultures are primarily utilized to identify infectious organisms in the gastrointestinal tract, not to assess fat levels. Lastly, the hydrogen breath test is designed to detect carbohydrate malabsorption, particularly lactose intolerance and other fermentable carbohydrates, rather than fats. Therefore, the Sudan stain for fecal fat is the most appropriate test for assessing fat malabsorption.