Can a blood test diagnose celiac disease without gluten exposure?

To receive an accurate diagnosis for celiac disease, many patients have to eat gluten regularly before undergoing lab tests. This is because the blood or gastroscopy exam relies on detecting antibodies that are triggered by gluten to prevent false negatives. However, eating gluten can cause symptoms such as diarrhea, abdominal pain, and bloating, which deters people from getting tested for celiac disease.

Because the path to diagnosis is difficult, there is a high possibility that many people are living with undiagnosed celiac disease. Fortunately, a study published in the journal Gastroenterology evaluated a blood test that measures an immune marker, interleukin 2 (IL-2), which has a high accuracy rate in diagnosing celiac disease without the need to consume gluten.

Researchers in Australia analyzed 181 blood samples from volunteers aged 18 to 75. Out of the 181 blood samples, 75 of those came from people with celiac disease who had been on a gluten-free diet for at least a year, 13 with untreated but active celiac disease, 32 with non-celiac gluten sensitivity, and 61 controls with no gluten sensitivity or celiac disease. With these blood samples, researchers utilized a diagnostic system to mix the samples with gluten to see if the IL-2 marker appeared. They found that the test detected celiac disease with up to 90% and 97% specificity, even in patients following a strict gluten-free diet.

Although this study has limitations, such as the lack of assessment of children and patients on immunosuppressants, the results are still significant and can be a game changer in how celiac disease is diagnosed. More research must be done before the exam can be used in clinical practice.