Anti-Glomerular Basement Membrane Antibody
Last updated: October 8, 2014
Synonyms: Anti-GBM antibody.
CPT Code: 83520
Description: Autoantibodies that react with components of the alveolar and glomerular basement membranes are known as GBM antibodies or anti-GBM antibodies. Recently, the specific antigenic epitopes recognized by GBM antibodies have been demonstrated on the α3 chain of type IV collagen.
Method: GBM antibodies, as well as antibodies specific to type IV collagen, are measured by ELISA or by indirect immunofluorescence.
Increased in: Anti-GBM antibodies are found in Goodpasture syndrome, which accounts for nearly 20% of all patients presenting with a pulmonary-renal syndrome (usually characterized by pulmonary hemorrhage and rapidly progressive glomerulonephritis). In addition to being a marker for Goodpasture syndrome, anti-GBM antibodies also plays a pathogenic role in causing the pulmonary and renal damage in this disease.
Indications: GBM antibodies are a sensitive test for Goodpasture syndrome because they occur in >95% of patients. Moreover, they are specific and are rarely seen in normal persons or patients with other pulmonary-renal syndromes. Although 10% of ANCA-associated vasculitis (usually pANCA+) will have anti-GBM antibodies, ANCA test should be negative in patients with Goodpastures.
Cost: The test is typically performed in a specialized laboratories and costs approximately $170 (range, $110–190).
BIBLIOGRAPHY
Lahmer T, Heemann U. Anti-glomerular basement membrane antibody disease: a rare autoimmune disorder affecting the kidney and the lung. Autoimmun Rev 2012;12:169-73. PMID: 22546293.
