Pathology tests database

Sample and container requirements

Plain serum

Minimum volume required

4 ml Blood

Special requirements

none

Patient preparation

None

Sample viability

Store at 4oC prior to sending to referral lab

Turnaround time

2-4 weeks

Reference range

negative

Clinical guidance

C3 nephritic factor is an IgG antibody which stabilises the alternative pathway C3 convertase leading to continuous C3 breakdown. If positive in patient with renal disease it strongly sugests mesangio-capillary nephritis. Approx two thirds of patients with partial lipodystrophy have a low C3 and circulating C3 nephritic factor, and have an increased tendency to develop mesangio-capillary nephritis. Clinical utility - MPGN Type II, familial lipodystrophy, transiently in post-streptococal glomerulonephritis. https://sheffieldlaboratorymedicine.nhs.uk/search-test.php?search=2969&testname=C3%20Nephritic%20Factor%20(C3NEF)

Notes

This test is only indicated if the C3 concentration is low