Specimen Requirements


Complement, Total (CH50)

Specimen Requirement

Collect SST or red top, allow to clot at room temperature for 60-65 minutes, centrifuge, transfer 1.0 mL serum to a screw top plastic vial, indicate sample type on tube and freeze immediately. Send frozen on dry ice.

Critical frozen.




Room temp: Unacceptable, Refrigerated: Unacceptable, Frozen: 30 days

Reference Range

By Report*


2 days performed Tuesday-Saturday

Clinical Use

Deficient or decreased levels of serum complement activity of the classical pathway are associated with a number of diseases. A normal CH50 assay indicates that C1 through C9 are present and functional in the serum being tested. Although CH50 can be used to assess the integrity of the classical pathway, it must not be used as a sensitive test for in vivo complement fixation. In vitro degradation can also cause low CH50 activity.

Test Code