The D-xylose absorption test is primarily used to differentiate between which two conditions?

The D-xylose absorption test is a diagnostic tool primarily used to evaluate the absorptive capacity of the intestine, particularly in distinguishing between pancreatic insufficiency and intestinal malabsorption due to other reasons.

In healthy individuals, D-xylose, a simple sugar, is readily absorbed in the intestines and excreted in the urine. If the intestines are functioning properly, a significant amount of D-xylose will be absorbed, and high levels will be found in the urine. However, if there is an issue with absorption (such as in conditions like celiac disease or Crohn's disease), low levels of D-xylose will be seen in the urine despite normal pancreatic function.

If pancreatic insufficiency is present, such as in conditions like chronic pancreatitis or cystic fibrosis, the body may have difficulty digesting and absorbing nutrients due to a lack of digestive enzymes rather than a primary problem with the intestinal lining itself. In such cases, the D-xylose absorption test helps to confirm that the issue lies with the pancreas rather than the intestinal mucosa, as patients with pancreatic insufficiency will still show decreased D-xylose absorption.

Thus, option B accurately describes the use of the D-xylose absorption