Key Advantages

  • Easily accessible blood spot testing for Zonulin – the key marker for intestinal permeability.


Zonulin is a protein that is synthesized in intestinal cells and liver cells. It is a key biomarker for intestinal permeability and is the only regulator of intestinal permeability that is reversible.

Zonulin is one of three ways the FIT test can diagnose a leaky gut, along with finding a sensitivity to Candida and multiple Food Sensitivities. It is estimated that anywhere between 50 and 100 percent of food intolerance sufferers have increased intestinal permeability.

Common Causes of Increased Intestinal Permeability Include:

  • Food Allergies
  • Food Sensitivities
  • Stress
  • Infections
  • Low Stomach Acid
  • And a range of other causes.

However, increasingly more conditions and causes are being connected with increased intestinal permeability.

Elevated levels of Zonulin have been associated with the following:

  • Coeliac Disease,
  • Autoimmune disease and
  • Multiple Sclerosis in addition to other chronic illnesses.

In a healthy gut, there are healthy cell junctions and good nutrient absorption. In a leaky gut, however, the Villi are damaged, there is poor absorption and the cell junctions are loose. This means that bacteria and unwanted items can pass through the gut, as seen in the picture to the right.

Zonulin Testing is best performed with the patient’s first FIT Test to provide a baseline for the Zonulin levels. This gives patients the opportunity to track their progress after implementing an elimination diet based on the FIT Test results. We recommend retesting when you retest your FIT.

If you have been authorised a test by your practitioner, or would like more information on how to conduct your functional test click HERE  If you already have a RN Labs account, please log in below.

If you do not have an account and would like to sign up for one, you can do so online HERE

Existing Users Log In