Complement C3 nephritic factor
| Category | Immunology |
|---|---|
| Test background |
C3 nephritic factors are autoantibodies that bind and stabilise the alternative pathway C3 convertase C3bBb leading to increased activation of the alternative complement pathway. They are commonly found in membranoproliferative glomerulonephritis (80% of patients with dense deposit disease, 50% with C3 glomerulonephritis) and partial lipodystrophy (80%). They can also be seen transiently in patients with post-streptococcal glomerulonephritis and very occasionally in healthy people (Levy Erez D, et al. J Allergy Clin Immunol. 2017 Jul;140(1):57-59.) |
| Clinical Indications |
C3 glomerulopathy (DDD, C3GN), partial lipodystrophy This is a specialised complement assay, please discuss with the laboratory before requesting. |
| Reference range | Negative |
| Sample & container required | Serum (SST) Separate and freeze immediately Transport frozen |
| Sample volume | 5-10 mL blood (1 mL serum) |
| Turnaround time | 28 days |
| Notes | Not currently tested in house, samples are referred to Royal Victoria Infirmary, Newcastle. |