Assay

Liver antibody screen

Key Words

Liver auto abs, LAB

Specimen Collection

Serum (Brown)

Turnaround time

7 days

Test indications

A variety of positive antibodies can be identified by this test.  Smooth muscle antibodies (SMA) are present in up to 75% of patients with autoimmune hepatitis type 1, however they can be found in other autoimmune diseases and can be present at low titres with limited clinical significance.  Anti-mitochondrial antibodies (AMA) of the M2 (pyruvate dehydrogenase complex) type are strongly associated with primary biliary cirrhosis (PBC) although they can be found in other autoimmune diseases such as systemic sclerosis. Positive AMA will be confirmed. Liver kidney microsomal; cytochrome p450 II D6 (LKM-1) antibodies are an uncommon but specific marker for a severe subset of patients with autoimmune hepatitis type 2 (formerly known as autoimmune chronic active hepatitis) and some drug induced hepatitis.

All samples are screened by indirect immunofluorescence. For any positive mitochondrial or LKM samples confirmatory testing is ordered by the laboratory.

In addition to M2 and LKM-1 antigens the confirmatory lineblot also tests for LC-1(cytosolic liver antigen type 1; forminotransferase-cyclodeaminase) and SLA/LP (Soluble liver antigen/liver-pancreas antigen). Both these antigens are associated with autoimmune hepatitis.

Methodology

Screen: indirect immunofluorescence;

Confirmatory testing: immunoblot

Interferences

No known methodological interferences

Reference Range

N/A

Analytical error

N/A

Reference change value

N/A

Minimum retesting interval

Liver antibody screen (LAB)- Requests made within one week of a previous request on a patient are intervened.

Liver lineblot (LIVB)- Repeat testing of liver lineblot antibodies is not usually indicated. Please contact the Immunology laboratory if a repeat is required.