Glomerular basement membrane (GBM) antibodies
| Category | Immunology |
|---|---|
| Test background |
Glomerular basement membrane (GBM) antibody disease is a rare autoimmune disorder in which circulating pathogenic antibodies are directed against an antigen normally present in the GBM and alveolar basement membrane. The target antigen is the alpha-3 chain of type IV collagen. The clinical syndrome encompasses a spectrum from mild or no renal involvement to a rapidly progressive glomerulonephritis. Significant proportions of patients develop pulmonary haemorrhage, and most individuals have signs of a generalised systemic illness. The combination of glomerulonephritis and pulmonary haemorrhage has been commonly referred to as Goodpasture’s syndrome, and over 90% of these patients have GBM antibodies. GBM antibody levels correlate with disease activity and are monitored during treatment. This test is performed by fluoroenzymeimmunoassay (Immunocap) on Phadia. All new positive GBM results are then confirmed by a qualitative immunoblot. |
| Clinical Indications |
Acute glomerulonephritis |
| Reference range | <7 U/ml |
| Sample & container required | Serum (RST rust top) |
| Sample volume | 5 -10 mL blood (1 mL serum) |
| Turnaround time | 5 days |