Mitochondrial Antibody, PBC Screen, AMA.

Special Precautions/Comments:

Method: Indirect Immunofluorescence (IIF). Calibration: Referenced to published or in-house pattern images. EQA scheme: UK NEQAS scheme for General Autoimmune serology. IQC: Commercial preparation.

Interferences: None known.

Interpretation: Results are reported as Negative or POS followed by a titre value for each of the patterns (ie SMA, GPC or AMA. If AMAs are present, the report will include an M2 result if new or relevant comment if known e.g. Known M2 Positive. A GPC result cannot be interpreted in the presence of a mitochondrial antibody. Test results are an aid to diagnosis and should not be considered as being diagnostic in themselves. Hence the test results should be used in conjunction with the patient’s clinical symptoms, the patient’s clinical history and any other available data, to produce an overall clinical diagnosis

 

Additional Information:

Indication: Primary Biliary Cirrhosis (PBC).

Background Information: The liver antibody screen utilises a composite tissue block of mouse liver kidney and stomach to identify anti-nuclear antibodies, gastric parietal cell antibodies, anti- mitochondrial cell antibodies and liver kidney microsomal antibodies all of which can be used to assess liver disease. Anti-Mitochondrial Antibodies (AMA) are strongly associated with Primary Biliary Cirrhosis (PBC), although they can be seen in other autoimmune conditions such as rheumatoid arthritis, systemic sclerosis and chronic liver disease [1]. Different types of AMA are described, based on antigen specificity, designated on a numeric basis: M1 to M9. The AMA associated with PBC is usually M2a or M2b [1]. Not all can be typed by IIF. M2 specific test is requested on all new AMA positive samples.

References: Jones DE. Pathogenesis of primary biliary cirrhosis. Clinics in liver disease. 2008. 12(2):305-321. Bogdanos DP, Invernizzi P, Mackay IR. Autoimmune liver serology: current diagnostic and clinical challenges. World Journal of Gastroenterology. 2008. 14(21):3374-3387. Muratori L, et al. Antimitochondrial antibodies and other antibodies in primary biliary cirrhosis; diagnostic and prognostic value. 2008. 12(2):261-276. PRU Handbook of autoimmunity. 4th Edition. 2007. [Ref 1] Wesierska-Gadek J, et al. Correlation of initial autoantibody profile and clinical outcome in primary biliary cirrhosis. Hepatology. 2006. 43(5):1135-1144. Czaja AJ. Autoantibodies in autoimmune liver disease. Advance in Clinical Chemistry. 2005. 40:127-164

See Also: ANA; SMA; GPC; AMA Type 2

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