Elmi Laboratories

C4 Complement blood test

Normal Reference Range

0.16 – 0.47 g/L

Test Information

To ascertain whether deficiencies or abnormalities in the complement system are the primary or secondary cause of a patient's disease or condition, complement assays, most frequently C3 is utilized. Angioedema, the cause of recurrent microbial infections, may be identified through complement testing. It could be utilized to aid in the diagnosis and activity monitoring of long-term autoimmune illnesses like SLE. In various immune complex-related illnesses and ailments such rheumatoid arthritis, glomerulonephritis, and vasculitis, it may be evaluated and tracked. Complement assists in the removal of immune complexes from the blood when they form in certain disorders, temporarily lowering complement levels, which serve as a sign of disease activity. The levels of complement C3 decrease as the disease becomes more aggressive.

Clinical Indications

• The diagnosis of HAE or cryoglobulinemia; the diagnosis of glomerulonephritis
• Serum electrophoresis reflex testing for the diagnosis of exclusion: acute phase increases versus underlying paraprotein disease.
• Usefulness in tracking autoimmune diseases (like SLE)
• Serial measurements are suggested rather than single point analyses for C3.

Sample Required

5mL serum sample blood tube is required for C3 and C4 blood test

Min. sample volume


Special Instructions and Precautions

Not applicable

Time Limits For Retrospective Testing

5 days

Any factors affecting the test

Not applicable

Turnaround Time

4 hrs

Referral centre (if applicable)

Not applicable

Test Code


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