**Question:** Cause of False positive D-xylose test includes all of the following, except

A. Malabsorption due to intestinal disease
B. Malabsorption due to portal hypertension
C. Malabsorption due to pancreatic insufficiency
D. Malabsorption due to small bowel obstruction

**Core Concept:**
The D-xylose test is a diagnostic test used to evaluate small bowel absorption in clinical practice. A false positive result can occur due to various factors affecting the small bowel absorption.

**Why the Correct Answer is Right:**
The correct answer (D) is excluded because small bowel obstruction does not directly affect the D-xylose absorption process. In contrast, A, B, and C involve malabsorption due to specific conditions affecting the small bowel and its functions (e.g., intestinal disease, portal hypertension, and pancreatic insufficiency).

**Why Each Wrong Option is Incorrect:**
A. Malabsorption due to intestinal disease (e.g., celiac disease) can lead to a false positive D-xylose test result as it affects the small bowel absorption and alters the test outcome.
B. Malabsorption due to portal hypertension can lead to a false positive D-xylose test result as it impairs small bowel function and increases the risk of malabsorption.
C. Malabsorption due to pancreatic insufficiency is another cause of false positive D-xylose test result as pancreatic enzymes are essential for the digestion and absorption of nutrients, including D-xylose.

**Clinical Pearl:**
Understanding the causes of false positive D-xylose test results is crucial for accurate interpretation of the test results in clinical practice. Recognizing these causes can help in differentiating between true small bowel dysfunction and a false positive test, leading to appropriate management decisions and patient care.