Follow-up test for complement activity screening when CH50 is low or absent and AH50 is normal and high suspicion remains for complement deficiency.
Quantitative Radial Immunodiffusion
Serum separator tube.
Allow specimen to clot for one hour at room temperature. Separate serum from cells ASAP or within 2 hours of collection. Transfer 1 mL serum to an ARUP Standard Transport Tube and freeze immediately. (Min: 0.3 mL)
CRITICAL FROZEN. Separate specimens must be submitted when multiple tests are ordered.
Non-frozen specimens. Specimens exposed to repeated freeze/thaw cycles. Specimens left to clot at refrigerated temperature.
After separation from cells: Ambient: 2 hours; Refrigerated: Unacceptable; Frozen: 2 weeks
Effective May 21, 2018
Decreased C2 levels may be associated with increased susceptibility to infection (especially pneumococcal infections), systemic lupus erythematosus-like disease, rashes, arthritis, nephritis, and with C1-Esterase deficiency. Increased C2 levels are associated with the acute phase response.
Laboratory Developed Test (LDT)
|Component Test Code*||Component Chart Name||LOINC|
|0050148||Complement Component 2||4484-2|
- C2 Antigen
- C2 Level
- Classical Pathway - Complement
- complement classical pathway
- Second componenet of complement