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Immunology Laboratory

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C3 Nephritic Factor

Also known as: C3NEF

C3 Nephritic Factor testing is performed by a referral laboratory. This assay is only available to members of Oxford University Hospitals NHS Foundation Trust.

C3 nephritic factor is an autoantibody to the alternate complement pathway's C3 convertase, C3bBb. C3NF stabilises this enzyme leading to an increase in the rate that C3 is activated (measured in this assay by an increase in C3c). The outcome of this is a markedly reduced C3 serum level. The antibody can be seen in membranoproliferative glomerulonephritis, MPGN and partial lipodystrophy. This assay is only indicated in patients with very low C3 levels.

  • C3NEF will only be performed on samples with an abnormally low C3
  • External users must provide the sample C3 level prior to C3NEF testing
    • External samples provided without a C3 level will be tested and billed for C3
    • C3NEFautoantibody testing will not be performed on samples with normal C3 levels

Specimen requirements

Serum 1ml; should preferably reach the Laboratory within four hours of venepuncture or separated serum sent frozen


Price on application

Laboratory turnaround time

7 days

Laboratory method


Reference range/units

Not applicable

Associated tests

Complement Levels

Sample stability

1 week (must be stored at -80ÂșC)

Shipping and storage

See specimen requirements.

Further information and contact details

For further information, email

Last reviewed:06 October 2023