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Test ID: EMA    
Endomysial Antibodies (IgA), Serum

Useful For Suggests clinical disorders or settings where the test may be helpful

Diagnosis of dermatitis herpetiformis and celiac disease

 

Monitoring adherance to gluten-free diet in patients with dermatitis herpetiformis and celiac disease

 

Because of the high specificity of endomysial antibodies for celiac disease, the test may obviate the need for multiple small bowel biopsies to verify the diagnosis. This may be particularly advantageous in the pediatric population, including the evaluation of children with failure to thrive.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

Circulating IgA endomysial antibodies are present in 70% to 80% of patients with dermatitis herpetiformis or celiac disease, and in nearly all such patients who have high grade gluten-sensitive enteropathy and are not adhering to a gluten-free diet.

 

For your convenience, we recommend utilizing cascade testing for celiac disease. Cascade testing ensures that testing proceeds in an algorithmic fashion. The following cascades are available; select the appropriate one for your specific patient situation. Algorithms for the cascade tests are available in Special Instructions.

-CDCOM / Celiac Disease Comprehensive Cascade: complete testing including HLA DQ

-CDSP / Celiac Disease Serology Cascade: complete testing excluding HLA DQ

-CDGF / Celiac Disease Gluten-Free Cascade: for patients already adhering to a gluten-free diet

To order individual tests, see Celiac Disease Diagnostic Testing Algorithm in Special Instructions.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

Report includes presence and titer of circulating IgA endomysial antibodies.

Negative in normal individuals; also negative in dermatitis herpetiformis or celiac disease patients adhering to gluten-free diet. See Results of IF Testing* in Cutaneous Immunofluorescence Testing in Special Instructions.

Interpretation Provides information to assist in interpretation of the test results

The finding of IgA-endomysial antibodies (EMA) is highly specific for dermatitis herpetiformis or celiac disease.

 

The titer of IgA-EMA generally correlates with the severity of gluten-sensitive enteropathy.

 

If patients strictly adhere to a gluten-free diet, the titer of IgA-EMA should begin to decrease within 6 to 12 months of onset of dietary therapy.

 

Occasionally, the staining results cannot be reliably interpreted as positive or negative because of strong smooth muscle staining, weak EMA staining or other factors; in this case, the results will be recorded as "indeterminate." In this setting, further testing with measurement of TTGA / Tissue Transglutaminase (tTG) Antibody, IgA, Serum and IGA / Immunoglobulin A (IgA), Serum levels are recommended.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

A negative result (absence of circulating IgA-endomysial antibodies) does not exclude the diagnosis of dermatitis herpetiformis or celiac disease.

 

Patients with mild gluten-sensitive enteropathy may have a negative result.

Clinical Reference Provides recommendations for further in-depth reading of a clinical nature

1. Peters MS, McEvoy MT: IgA antiendomysial antibodies in dermatitis herpetiformis. J Am Acad Dermatol 1989;21:1225-1231

2. Chorzelski TP, Buetner EH, Sulej J, et al: IgA anti-endomysium antibody: a new immunological marker of dermatitis herpetiformis and coeliac disease. Br J Dermatol 1984;111:395-402

3. Kapuscinska A, Zalewski T, Chorzelski TP, et al: Disease specificity and dynamics of changes in IgA class anti-endomysial antibodies in celiac disease. J Pediatr Gastroenterol Nutr1984;6:529-534

Special Instructions and Forms Describes specimen collection and preparation information, test algorithms, and other information pertinent to test. Also includes pertinent information and consent forms to be used when requesting a particular test