Glomerular Basement Membrane Antibodies, IgG, Serum

CPT CODE:

USEFUL FOR:

Evaluating patients with rapid onset renal failure or pulmonary hemorrhage, as an aid in the diagnosis of Goodpasture syndrome

SPECIMEN REQUIRED:

Draw blood in a plain, red-top tube(s) or a serum gel tube(s). Spin down and send 0.5 mL of serum refrigerated.

TRANSPORT TEMPERATURE:

Refrig\Frozen OK\Ambient NO

CLINICAL INFORMATION:

Antibodies to glomerular basement membrane antigens (GBM antibodies) cause glomerulonephritis, Goodpasture syndrome (glomerulonephritis, often with rapid onset renal failure, and pulmonary hemorrhage), and, less commonly, pulmonary hemosiderosis.(1) Nephrogenic GBM antigens are associated with the noncollagenous carboxyl extension of type IV procollagen. The immunologic stimuli that elicit production of GBM antibodies are not known. There is some evidence of a genetic association with HLA-DR2.
GBM antibody-mediated glomerulonephritis and Goodpasture syndrome occur with a bimodal age distribution primarily in males ages 20 to 40 and in patients older than age 50. Glomerulonephritis without pulmonary involvement is more common in the older age group, and shows a female predominance.

CLINICAL INTERPRETATION:

Positive results are consistent with Goodpasture syndrome. GBM antibodies detected by immunoassay have been reported to be highly specific for Goodpasture syndrome. The sensitivity of this test approaches 87% in untreated patients with systemic disease.(1)

REFERENCE VALUES:

<1.0 U (negative)                              

> or =1.0 U (positive)

Reference values apply to all ages.