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Is it beneficial to get a screening test for Celiac disease?

Is it beneficial to get a screening test for Celiac disease?

Last Reviewed : 12/18/2020
Is it beneficial to get a screening test for Celiac disease?

Celiac disease has become prevalent among young people. Also known as coeliac or sprue, celiac disease is a serious disorder that triggers a response in intestine as a result of dietary gluten consumption. According to statistics, in the United States, the prevalence of celiac disease is appreciably low, maintaining 0.71% . In one report, researchers found that most of the cases of celiac disease remain undiagnosed.

Celiac Disease Screening

Screening for celiac disease is not recommended for asymptomatic people or general population. It is done in only selected individuals who present with gastro intestinal symptoms suggesting celiac disease. Similarly, individuals who are at high risk of developing the disease like the first degree relatives of people with celiac disease will need the screening. In addition to that, people suffering from auto-immune disorders or genetic abnormalities that are commonly associated with celiac disease like type1 diabetes mellitus, auto immune thyroid disease, down’s syndrome, turner syndrome or selective Ig A deficiency will definitely need the test.

The United States Preventive Services Task Force has graded screening for celiac disease in asymptomatic individuals as ‘I’ statement, implying that current evidence regarding screening is insufficient to assess the benefits and harms.

Basically, when a patient presents with symptoms suggestive of celiac disease (such as diarrhoea, abdominal bloating, discomfort and steatorrhea or fatty stools), certain tests are done to screen such symptomatic individuals for celiac disease. So, serological tests measure elevated antibody levels in the blood due to body’s reaction to gluten.

Test used for Celiac Disease Screening

Today, tests used for screening are discussed below.

1. tTG Antibodies (tTG-IgA): Well, this is an immune globulin-based serological test called as tissue transglutaminase antibody test. It detects the presence of an immune globulin directed against an enzyme in the intestinal system.

The disadvantage associated with this test is high false positives that happens when antibodies are present due to the presence of some other disease. Incidence of such false positives is high in areas where the disease burden of gastro intestinal diseases is higher. It may also show false negatives when done in children below 2 years of age or individuals with a selective deficiency of IgA immunoglobulin.

2. Anti-endomysial antibody test: Here’s another test that is used for screening celiac diseases. However, this is not being commonly used these days due to availability of tTG test. It is used along with tTG to diagnose celiac disease in children below 2 years of age.

3. Anti-gliadin test: Aside from the tests we have discussed so far, anti-gliadin test is another test used for that purpose. So, this tests for antibodies against gliadin. It not used these days due to high occurrence of false positives and negatives. Nonetheless, detection of antibodies against deamidated gliadin peptides is a modification of anti-gliadin test being used these days.

4. Genetic testing: Nowadays, genetic testing is becoming popular among lab scientists. Indeed, it involves detection HLA DQ2, HLA DQ8, or parts of these genes. A negative test helps in ruling out the diagnosis of celiac disease, but a positive result doesn’t confirm it.

Tests used for screening celiac disease have high sensitivity. As a result, they also have a very high incidence of false positives. In asymptomatic individuals or in general population, the positive predictive value of these tests has been shown to be very low.

Harmful effects of screening in asymptomatic individuals

  • False-positives and unnecessary serological testing and biopsy leading to unnecessary anxiety and complications from testing.
  • It also has a potential danger of over diagnosis as some of the patients diagnosed with celiac disease may actually never show any symptoms of the disease.
  • Some asymptomatic individuals who have shown positive serological tests may not be willing to undergo biopsy. Nevertheless, such individuals would always avoid gluten to prevent possible complications of celiac disease leading to consumption of costly, gluten-free diet. Well, this increases the disease burden on the community.
  • It is important to note that the serological test can only screen the disease but not confirm the diagnosis. Consequently, gluten challenge test and intestinal biopsy are always done to confirm the diagnosis. But even after the serological tests have turned out to be positive for celiac disease, consumption of gluten must not be stopped till the diagnosis is confirmed. But if an individual adopts gluten free diet prior to diagnosis, the tests used to diagnose celiac disease become unreliable, and can be falsely negative.

Conclusion

This piece primarily explains all you need to know about the screening test for celiac disease. Do you fall into the asymptomatic category? Making an appointment for that screening may not be ideal for you. However, if you don’t belong to this class of people, you should go ahead and have the test. To all health experts who are reading this guide with a view to learning why it is not advisable to screen asymptomatic people, now you know the reasoning behind it. After reading this piece, we strongly believe that you are armed with adequate vital information to make informed decision.

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