Anti-Glomerular Basement Membrane Antibody Dx

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.

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