"Leaky gut" (gut permeability) test

What this test is

This test checks whether your gut lining lets substances through. Normally these substances would not cross into your blood. The idea is often called 'leaky gut.' It is done as a urine test after you drink a sugar solution. Or it is done as a 'zonulin' blood test. 'Leaky gut syndrome' is not a recognized medical diagnosis. For the zonulin blood test, researchers looked closely at common versions. They found the tests were not measuring the protein they claim to measure. That means a result is hard to trust or act on. If you have symptoms that worry you, it is better to look directly for the cause. This could be celiac disease or a specific food trigger.