Glomerular Basement Membrane Antibodies, IgG, Serum

Casandra

Casandra Test Code MC16413Version 1 (DRAFT)

Performing Lab

Lab Mayo Clinic LabLab Test ID GBMCPT Code 83516

Glomerular Basement Membrane Antibodies, IgG, Serum

Clinical Use

Use

This test is useful for evaluating patients with clinical features of anti-glomerular basement disease, including rapidly progressive glomerulonephritis or pulmonary hemorrhage. Anti-glomerular basement (GBM) disease is a rare autoimmune disease associated with the presence of anti-GBM antibodies, particularly of the IgG isotype, which bind to the non-collagenous domain 1 (NC1) of the alpha3 chain of type IV collagen. These antibodies can trigger complement activation, leading to vascular necrosis and damage to the glomerular basement membrane. Evaluating the presence of these antibodies is crucial for diagnosing anti-GBM disease, particularly in patients with compatible clinical symptoms.

Special Instructions

If the patient is being evaluated for autoimmune skin disease, consider ordering CIFS / Cutaneous Immunofluorescence Antibodies (IgG), Serum for anti-intercellular substance (ICS) and antibasement membrane zone (BMZ) antibodies. Ensure serum is centrifuged and aliquoted into a plastic vial before submission.

Limitations

A positive result must be interpreted in the clinical context as it is not solely diagnostic for anti-GBM disease. A negative result does not exclude the possibility of anti-GBM disease, especially in patients treated with immunosuppressants or plasmapheresis prior to testing. Diagnostic sensitivity and specificity are suggested by a pooled sensitivity of 93% and specificity of 97% across various immunoassay methods. Clinical interpretation should consider these parameters, and higher antibody titers may correlate with increased mortality without prompt treatment.

Test Details

New York Approved