Can You Trust a Negative Celiac Blood Test?
The blood test most commonly used to diagnose celiac disease is called the anti-tissue transglutaminase, or anti-tTG. It looks for the presence of antibodies (IgA) against the tTG enzyme. If your screening test is positive, your doctor should refer you to a gastroenterologist who can do a biopsy to confirm celiac disease – this is still the gold standard of diagnosis. But what happens when the results come back negative? Can you trust a negative celiac disease blood test?
A new study, published in the Journal of Clinical Gastroenterology, calls the sensitivity of the TTG-IgA test into question and raises the issue of frequent false negatives. According to the study a negative result of the test should be “viewed cautiously” noting that further testing should often be done.
So, if you are still feeling unwell after a negative TTG-IgA ask for a referral to a gastroenterologist. A gastroenterologist will ensure that you get the follow up care you need…for life. Until your appointment with the gastroenterologist, continue to consume at least the equivalent of one to four slices of bread containing gluten every day for the biopsy to be accurate. And first-degree relatives (parents, siblings, children) should also be screened for celiac disease as they have a 10% risk of developing celiac disease at any age if your final results do come back positive.
Once you have a diagnosis - or confirm there is no diagnosis to be had - then you can roll up your sleeves and work with nutrition to improve symptoms and start feeling good again.
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Photo by Karolina Grabowska
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Hujoel, Isabel A. MD*; Jansson-Knodell, Claire L. MD†; Hujoel, Philippe P. PhD‡; Hujoel, Margaux L.A. PhD§; Choung, Rok Seon MD, PhD*; Murray, Joseph A. MD*; Rubio-Tapia, Alberto MD∥ Estimating the Impact of Verification Bias on Celiac Disease Testing, Journal of Clinical Gastroenterology: April 2021 - Volume 55 - Issue 4 - p 327-334 doi: 10.1097/MCG.0000000000001361