Test Overview
Clinical Utility
CH50 is a screen for complement deficiencies or significant activation. Measures the relative activity of the total classical pathway (C1-C9).
Complement activity is very labile and reliable results depend on correct handling of the specimen.
Method
Spectrophotometry
Result Included
Complement - Total (CH50)
Aliases/Synonyms
Total Complement Function Assay
Specimen
Specimen Type
SerumVolume
Sample Volume
2 mL
Minimum Volume
0.5 mL
Collection & Handling
Handling Information
Allow filled tube to clot at 22 – 37°C for 30 – 60 minutes. Centrifuge at room temperature. Aliquot into storage tube and freeze as soon as possible. Store and send frozen.
Additional Information
CH50 may be decreased by: delayed separation of serum, insufficient clotting, prolonged storage at room temperature, use of plasma, presence of immune complexes, cryoglobulins, bacteria or particulates.
Stability
| Frozen |
|---|
| 14 days |
Stable at least 30 days when stored at -80°C
Rejection Criteria
| Criteria | Specification |
|---|---|
| Hemolysis | Gross |
| Lipemia | Present |
| Specimen | Plasma |
Performance & Interpretation
Turnaround Time
6 days
Results
-
Complement - TotalU/mL42 - 95
Comment
Analytical range 14 - 105 U/mL. Results less than or greater than these limits will be reported as such.
Referral Location
Canada
Interface & Setup
HL7 Interface Codes
| Order Code | Result Name | Result Codes | Units |
|---|---|---|---|
| CH50 | CH50 | 8787 | U/mL |
Test Version
Last Updated
2026-02-17