Skip to content
Blood Test Tracker

Endomysial Antibody IgA (EMA)

A blood test for IgA antibodies that are very specific for celiac disease, usually used to back up a positive tTG-IgA result.

AI-verified against cited sources. Awaiting expert reviewAlso called EMA-IgALOINC 27038-9

What it is

Endomysial antibodies are made by the immune system in people with celiac disease when they eat gluten. The lab mixes your serum with a thin slice of animal tissue, such as monkey esophagus, and looks under a microscope for a glowing pattern around the smooth muscle fibers. The result is reported as negative or positive, often with a titer, which is how far the sample can be diluted and still glow (for example 1:10 or 1:20). The target of these antibodies is the same enzyme that the tTG test measures.

Why it matters

A positive EMA strongly supports celiac disease, especially when the tTG-IgA test is also positive. It is usually ordered after tTG-IgA, because tTG-IgA is the preferred single test for people older than 2. In some children, a very high tTG-IgA result plus a positive EMA in a second blood sample can support the diagnosis without a biopsy. A negative EMA makes celiac disease less likely, but it does not rule it out, especially with IgA deficiency or a gluten-free diet.

If it’s high

A positive result means your blood contains antibodies that are closely linked to celiac disease. In one study of 972 adults, EMA was positive in 97.4% of people with celiac disease and in none of the people without it. Harmless explanations are uncommon for this test. Even so, in adults the diagnosis is usually confirmed with a small-bowel biopsy while you are still eating gluten.

Common causes

  • Celiac disease
  • Potential celiac disease, where the blood tests are positive but the small-bowel biopsy looks normal
  • Dermatitis herpetiformis, an itchy, blistering skin rash related to celiac disease

What can help

  • Keep eating gluten until your clinician says testing is finished, because stopping early can hide the disease
  • Ask about the next step, such as a biopsy of the small intestine or other celiac tests
  • If celiac disease is confirmed, ask for a referral to a dietitian who knows gluten-free eating

What can affect your result

  • Gluten intake: eating gluten raises celiac antibodies, and a gluten-free diet lowers them
  • IgA deficiency (about 1 in 400 to 1 in 800 people overall, and 2 to 3% of people with celiac disease)
  • Age: the test is less sensitive in children younger than 2
  • The tissue slide and reader: methods differ between labs, and the pattern is judged by eye
  • Family history: close relatives of people with celiac disease are more likely to have it
  • Gluten intake: the test works best while you are eating gluten. A gluten-free diet lowers celiac antibodies and can turn a positive result negative. MedlinePlus advises eating gluten for a few weeks before testing.
  • IgA deficiency can cause a false-negative result because this is an IgA test. Labs often check total IgA or use IgG-based tests instead.
  • Children under about 2 years old may be more likely to have a false-negative result.
  • The slide is read by eye under a microscope, so the result depends on the lab's method and the reader.
  • ARUP rejects plasma and severely lipemic, contaminated or hemolyzed samples for its EMA test.

Celiac antibodies fall after a strict gluten-free diet. About 80% of people test negative after 6 to 12 months, and more than 90% after 5 years.

When to talk to a clinician

Talk with a clinician soon if you have a positive result along with ongoing diarrhea, weight loss, anemia, bloating or an itchy blistering rash. Seek urgent care for severe belly pain, vomiting that will not stop or signs of dehydration such as dizziness and very little urine.

Questions you could ask

  • Was my total IgA checked, in case it could affect this result?
  • If I am already eating gluten-free, how does that change the way you read this result?
  • Does this result fit with my tTG-IgA, and what is the next step?
  • Do I need a small-bowel biopsy, and should I keep eating gluten until then?
  • Should my close relatives be tested?

Questions people ask

Why was an EMA ordered after my tTG test?

EMA is very specific for celiac disease, so it is often used to back up a positive tTG-IgA result or to help settle an unclear one. Both tests look for antibodies to the same target, but EMA is read under a microscope and needs an experienced reader.

Can I have celiac disease if my EMA is negative?

Yes, though it is uncommon. In one adult study, 9 of 637 people with a negative EMA still had celiac disease. Causes included IgA deficiency, celiac disease with negative blood tests, and a negative EMA with a positive tTG. A gluten-free diet or a young age can also lead to a negative result.

What does the titer mean?

The titer is the highest dilution of your blood that still shows the glowing pattern. A higher number, such as 1:80, means more antibody than 1:10. Labs start at different dilutions, so the main question is positive or negative. Antibody tests, including EMA in some cases, can also be used to follow whether a gluten-free diet is working.

Show the science and sources

For clinicians and researchers

IgA endomysial antibodies bind the connective tissue around smooth muscle fibers. The main target is tissue transglutaminase (TG2), which ARUP notes in its interpretive comment. They are detected by indirect immunofluorescence on primate tissue (monkey esophagus or jejunum are common substrates, and human umbilical cord is also used) and reported qualitatively with an endpoint titer. Screening dilutions and positive thresholds vary: ARUP's reference is less than 1:10, and one commercial kit used in a published adult cohort called a titer of 1:5 or more positive. Mayo's IgA EMA titer test is only run as a reflex after a positive screen. In that cohort of 972 adults, sensitivity was 97.4% and specificity 100%. Both EMA and tTG-IgA are reported as 90 to 100% sensitive and close to 100% specific in the literature. The false negatives were IgA deficiency (3 of 9 missed cases), seronegative celiac disease (3) and EMA-negative, tTG-positive cases (3). IgG-class EMA exists but is not widely available. Because the read is subjective and needs an experienced evaluator, tTG-IgA ELISA is the usual first-line test, and EMA serves as a more specific second step. Older ESPGHAN criteria allowed biopsy-free diagnosis in children with symptoms, tTG-IgA above 10 times the upper limit of normal confirmed by a positive EMA in a second sample, and HLA-DQ2 or DQ8.

LOINC 27038-9 (primary), 10863-9, 10362-2, 46126-9. Specimen: serum.

Sources

  1. Endomysial Antibody, IgA by IFA (ARUP test 0050736), ARUP Laboratories (2026)
  2. Endomysial Antibodies, IgA, Titer, Serum (Non-Orderable) (Mayo Clinic Laboratories test EMAT), Mayo Clinic Laboratories (Extended Catalog mirror, testcatalog.org) (2026)
  3. Endomysial Antibodies, IgG, Serum (Mayo Clinic Laboratories test EMAIG), Mayo Clinic Laboratories (Extended Catalog mirror, testcatalog.org) (2026)
  4. Celiac Disease Screening, MedlinePlus (U.S. National Library of Medicine)
  5. ACG clinical guidelines: diagnosis and management of celiac disease, American Journal of Gastroenterology 2013;108:656-676 (2013)
  6. Biopsy-Sparing Diagnosis of Coeliac Disease Based on Endomysial Antibody Testing and Clinical Risk Assessment, Alimentary Pharmacology & Therapeutics 2025;61:1794-1804 (2025)
  7. Automatic classification of IgA endomysial antibody test for celiac disease: a new method deploying machine learning, Scientific Reports 2019;9:9217 (2019)
  8. LOINC codes verified with the NLM Clinical Tables LOINC search (e.g. 27038-9), U.S. National Library of Medicine

AI-verified against cited sources. Awaiting expert review. Last reviewed 2026-10-03. How we build and check these pages.

Related markers