Gut
EPX (eosinofiele proteïne x)
A protein from eosinophils, white blood cells that are active in allergy and parasites; its meaning in stool is not established.
Everything about this testWhat it measures
EPX (eosinophil protein X) is a protein from eosinophilic granulocytes, white blood cells that become active mainly in allergic reactions and in infections with worms or other parasites. When these cells are active in the bowel wall, EPX ends up in the stool. The test measures how much EPX is in a stool sample.
- Activity of eosinophils in the gut, for example with a parasite or an allergic reaction; the meaning for diagnosis has not been established
High
A raised value may fit activity of eosinophils in the gut. This occurs with an infection with worms or other parasites, with a food allergy, with chronic inflammatory bowel disease and with a rare inflammation of the gut caused by eosinophils. There is no condition for which EPX in stool is used to make a diagnosis. A food allergy is not diagnosed with this test.
Low
A low value is the usual result and has no further meaning. It does not rule out a food allergy or a parasite.
If your result is abnormal
With an abnormal result without symptoms, no follow-up is usually needed. With bowel symptoms, the GP can request calprotectin in the stool and blood tests, and refer you to a gastroenterologist if there are signs of a chronic inflammation of the bowel.
Reliability
For most markers in this group, it has not been shown what an abnormal value means, in people without symptoms and also not with bowel symptoms. To detect or rule out bowel inflammation, calprotectin in the stool (a separate test) has been studied much better. Some are sometimes used in hospital for a specific question; others are mainly used in scientific research. A "leaky gut" is not a recognized diagnosis, and none of these markers can make such a diagnosis.
Limitations
- Anti-inflammatory painkillers (NSAIDs), a recent intestinal infection, blood in the stool and menstrual blood can raise the value.
- Loose or, on the contrary, hard stool changes the concentration in a stool sample.
- Measurement methods are not standardized; cutoff and reference values differ per laboratory.
- The substances can break down if the stool is in transit for a long time or is stored warm.
How common is this
Bowel symptoms are common: according to the guideline, irritable bowel syndrome affects about 4 in 100 adults in the Netherlands. Chronic inflammatory bowel diseases such as Crohn's disease and ulcerative colitis are much rarer; the guideline gives no Dutch figure for them. How often an abnormal result for these markers occurs in people without symptoms is not known.
Who is this useful for
In people without symptoms, an abnormal result says little, because the meaning has not been established and a passing infection or a painkiller can raise the value. With long-lasting diarrhea or abdominal symptoms, the GP uses calprotectin in the stool to rule out a chronic inflammation of the bowel, and a blood test if celiac disease is suspected. With blood in the stool, unintended weight loss, diarrhea at night or new bowel symptoms after age 50, this test is no substitute for a visit to the GP.
Sources
Always discuss an abnormal result with your GP. If a result is strongly abnormal, we try to reach you as soon as possible. Read your result yourself as well and contact your GP if in doubt. A test does not make a diagnosis. Read more about risks and results