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Test ID AMA Mitochondrial Antibodies (M2), Serum

Reporting Name

Mitochondrial Ab, M2, S

Useful For

Establishing the diagnosis of primary biliary cirrhosis

Specimen Type


Specimen Required


Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL

Specimen Minimum Volume

0.4 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 21 days
  Frozen  21 days

Reference Values

Negative: <0.1 Units

Borderline: 0.1-0.3 Units

Weakly positive: 0.4-0.9 Units

Positive: ≥1.0 Units

Reference values apply to all ages.

Day(s) Performed

Monday through Saturday

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
AMA Mitochondrial Ab, M2, S 51715-1


Result ID Test Result Name Result LOINC Value
AMA Mitochondrial Ab, M2, S 51715-1

Clinical Information

Antimitochondrial antibodies (AMA) are detectable by indirect immunofluorescence in more than 90% of patients with primary biliary cirrhosis (PBC), but this method also detects AMA of differing specificities in other diseases. The mitochondrial antigens recognized by AMA in patients' sera have been classified numerically as M1 through M9, with the M2 antigen complex recognized by AMA in sera from patients with PBC. M2 antigen is comprised of enzyme proteins of the 2-oxoacid dehydrogenase complex that are located on inner mitochondrial membranes. Included in this group of autoantigens are the pyruvate dehydrogenase complex, and 2-oxoglutarate dehydrogenase complex.


Positive results for antimitochondrial antibody (AMA) of M2 specificity are highly specific for primary biliary cirrhosis (PBC), and false-negative results are rare.


A positive result for AMA of M2 specificity in a patient with clinical features of PBC is virtually diagnostic for this disease.

Clinical Reference

1. Rich R, Fleisher T, Shearer W, et al: Inflammatory hepatobiliary cirrhosis. In: Clinical Immunology Principles and Practice. 3rd ed. Elsevier; 2008

2. Muratori L, Granito A, Muratori P, et al: Antimitochondrial antibodies and other antibodies in primary biliary cirrhosis: diagnostic and prognostic value. Clin Liver Dis. 2008;12:261-276

3. Kaplan MM, Gershwin ME: Primary biliary cirrhosis. N Engl J Med, 2005;353(12):1261-1273. doi: 10.1056/NEJMra043898

4. Van Norstrand MD, Malinchoc M, Lindor KD, et al: Quantitative measurement of autoantibodies to recombinant mitochondrial antigens in patients with primary biliary cirrhosis: relationship to levels of autoantibodies to disease progression. Hepatology. 1997;25(1):6-11

Report Available

1 day

Method Name

Enzyme Immunoassay (EIA)


If not ordering electronically, complete, print, and send 1 of the following forms with the specimen:

-General Request (T239)

-Gastroenterology and Hepatology Client Test Request (T728)