Understanding celiac testing and genetic testing

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Katarina Mollo MEd, RDN, LDN
Q: Can you test negative for celiac disease and possibly be positive 2 years later? Also, can you have the gene for celiac disease and test negative?

Answer


Yes, you can develop celiac disease at any time during your lifetime if you have the compatible genes (HLA-DQ2 or HLA-DQ8). Up to 40% of the population have the gene for celiac disease, but not everybody with the gene(s) will develop celiac disease. It is estimated that less than 5% of people with the compatible genes will develop celiac disease (1). It is unknown what turns the gene on, but once the disease is activated, it cannot be reversed.

To develop celiac disease, you need three things:

  1. A genetic predisposition
  2. Exposure to gluten
  3. A physical or environmental trigger (unknown)

It is recommended that first degree relatives of those with celiac disease get tested (antibody test) as it is more common in those with a relative with celiac disease. Recommendations for frequency of testing vary, but ranges from every 2-5 years. A genetic test can sometimes be used as a first step to determine if you should go on with further testing. It won't tell you if you have celiac disease, only if you carry the gene. But if you do not have the gene then celiac disease is very unlikely.

Celiac disease prevalence:

1st degree relative with celiac disease (parent, child, sibling): 1 in 22

2nd degree relative with celiac disease (aunt/uncle/grandparents): 1 in 39

US population: 1 in 133 (2)

Note: You can also test falsely negative on the antibody test and the endoscopy if you are already on a gluten-free diet. Once on a gluten-free diet, antibodies to gluten will start to drop in the blood and the intestine will start to heal which may lead to a false negative result. It is very important that you do not start a gluten-free diet before testing and diagnosis.

Read more here about celiac disease testing: https://nationalceliac.org/celiac-disease-questions/tests-for-celiac-disease/

Read more here about celiac disease genes:
https://nationalceliac.org/celiac-disease-questions/celiac-genes/

References:

  1. UChicago Medicine. Celiac Answer Bank. Celiac Disease Center Website. http://www.cureceliacdisease.org/faq/what-percentage-of-those-with-the-genes-will-develop-celiac-disease/. Published August 2012. Updated 2018.
  2. Fasano A, Berti I, Gerarduzzi T, Not T, Colletti RB, Drago S, Elitsur Y, Green PH, Guandalini S, Hill ID, Pietzak M, Ventura A, Thorpe M, Kryszak D, Fornaroli F, Wasserman SS, Murray JA, Horvath K. Prevalence of celiac disease in at-risk and not-at-risk groups in the United States: a large multicenter study. Arch Intern Med. 2003 Feb 10;163(3):286-92.

Reviewed October 21, 2022.

Note: This information is provided by NCA and Katarina Mollo MEd, RDN, LDN, NCA's Director of Education. This information is meant for educational purposes only and is not intended to substitute for personalized medical advice or replace any medical advice provided directly to you by your health care provider. No liability is assumed by the NCA or Katarina Mollo, MEd, RDN, LDN by providing this information.

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