Adult-Gerontology Clinical Nurse Specialist (CNS) Practice Exam

What is the standard test used to diagnose leaky gut syndrome?

1. BUN

2. Food allergy test

3. Microbial flora testing

4. Mannitol and lactulose testing

The correct answer is: Mannitol and lactulose testing

Mannitol and lactulose testing is widely recognized as the standard method for evaluating intestinal permeability, which is often associated with leaky gut syndrome. This test involves the oral administration of two different sugars: mannitol and lactulose. Mannitol, a small molecule, is easily absorbed by a healthy intestine. In contrast, lactulose, a larger molecule, is less readily absorbed. After ingestion, the amounts of these sugars that appear in the urine are measured. If the intestinal barrier is compromised, as seen in leaky gut syndrome, higher levels of lactulose will be excreted in the urine since larger particles can seep through the damaged intestinal lining. Mannitol levels may not be as significantly affected. Consequently, the ratio of lactulose to mannitol in the urine can indicate the integrity of the intestinal barrier. This testing method thereby provides clinical insight into the condition of the gut lining, which is key in diagnosing leaky gut syndrome. In the context of the other testing options, while they may have relevance in gastrointestinal health assessments, they do not specifically target the assessment of intestinal permeability in the same direct way that mannitol and lactulose testing does. For instance, BUN (Blood Urea Nitrogen) levels primarily gauge kidney