Category: Gastroenterology & Hepatology
Test Code: 167
Disease: Autoimmune Liver Diseases
Methodology: ELISA
Reference Range: Negative: <20 ; Borderline: 20-24.9 ; Positive: ≥25
CPT Code: 83516
Schedule / Turnaround Time: Assay performed once every two weeks. Report availability is two weeks from the time of specimen receipt.
Specimen Requirements:

Specimen need not be refrigerated or frozen. Collect 2-3 ml of blood in a red top or serum separator tube. If possible, separate serum from clot and place into white tube provided with Immco Diagnostics’ collection kits. If separation facilities are not available, the blood can be sent in the tube used for collection.

Sample Stability:

Sample is stable at ambient temperature during shipment. If sample is stored prior to shipment, it is stable refrigerated (2-8˚C) up to five days and frozen (-20˚C or lower) up to one year.


Serological assays are important aids to the recognition and diagnosis of PBC since many antibodies associated with PBC are present before symptoms become evident. Anti-mitochondrial antibodies (AMA), detected by indirect immunofluorescence assay (IFA), are the classic serological markers of PBC. AMA are found in up to 90-95% of PBC patients. At least 5-10% of PBC patients test negative for AMA by both IFA and ELISA assays. The failure to find AMA or other markers of PBC can contribute to the delay in the diagnosis of PBC and the possibility of additional liver damage. About 50% of sera from PBC patients contain antinuclear antibodies (ANA). One ANA specifically associated with PBC is a nuclear rim/ membranous staining, characteristic of the nuclear membrane protein gp210. This protein is part of a complex of proteins that form pores on the nuclear membrane. Anti-gp210 antibodies can be detected in approximately 25% of all PBC patients and 10-50% of AMA-negative PBC patients. Although gp210 antibodies have a relatively low sensitivity for PBC, their specificity appears to be greater than 99%. In addition, gp210 antibodies may identify a subgroup of patients with a more severe disease course. The presence of gp210 antibodies can strengthen the diagnosis of PBC in cases where the clinical presentation may be unclear.