Effective February 4, 2013, there will be a change in the methodology of the Anti-Mitochondrial Antibody (AMA) and Anti-Smooth Muscle Antibody (ASMA) testing from an Immunofluorescence Assay to a semi-quantitative ELISA method.

The QUANTA Lite™ PBC Screen IgG/IgA ELISA is an enzyme-linked immunosorbent assay (ELISA) for the semi-quantitative detection of mitochondrial antibodies, gp210 antibodies and sp100 antibodies of the IgG and/or IgA class in human serum. The presence of mitochondrial, gp210 and sp100 antibodies can be used in conjunction with clinical findings and other laboratory tests to aid in the diagnosis of primary biliary cirrhosis (PBC).

Although most conventional assays only detect, IgG AMA antibodies, IgA AMA antibodies are present in the serum, bile, saliva end urine of individuals with PBC.  It has been suggested that this secretory anti-PBC IgA may play a role in the pathogenesis of PBC.  Patients with suspected autoimmune liver disease, but not satisfying all the classical criteria, can be clinically challenging. Individuals with “AMA-negative” PBC fall into this group. New assays for detection of antibodies to gp210, sp100 and AMA utilizing the enhanced sensitivity MIT3 antigen, have reduced the number of PBC patients without serological evidence of PBC.

Reference Range:	Negative	<20 units
	Equivocal	20.1 – 24.9 units
	Positive	>25

The QUANTA Lite™ Actin IgG ELISA is an enzyme linked immunosorbent assay (ELISA) for the semi-quantitative detection of IgG antibodies to the actin component of smooth muscle in human serum.  The presence of Actin antibodies can be used in conjunction with clinical findings and other laboratory tests to aid in the diagnosis of autoimmune liver diseases such as autoimmune hepatitis and primary biliary cirrhosis.

Reference Range:	Negative	<20 units
	Weak Positive	20-30 units
	Positive	>30

Specimen type, minimum specimen requirements, test availability and turnaround time are the same as the Anti-Mitochondrial Antibody and Anti-Smooth Muscle assay.

Questions should be directed to Sergei Syrbu, MD, PhD, medical director of the Immunopathology Laboratory (386-7372, sergei-syrbu@uiowa.edu).