Complement (C3, C4 Levels)

Department of Immunology

Notes

• Investigation into complement activation including immune complex disease.
• Low C3 and C4 levels can be seen in active SLE.
• Very low C3 in isolation can be seen in post streptococcal glomerulonephritis and C3 nephritic factor related disease.
• Very low C4 in isolation can be associated with C1 inhibitor deficiency. If C4 is normal, C1 inhibitor deficiency is very unlikely.

Sample Requirements

Clotted blood. (No patient preparation or special handling required).

Adult

5ml Gold-top SST tube or 3.5ml Rust-top gel tube (Trust users only)

Paediatric

1ml Serum Sample

Time Limit for Add-ons

3 days

Turnaround Times

5 days

Reference Ranges