Complement, Total (CH50)
Also known as: CH50, Total Hemolytic Complement
Use
Evaluate and follow up SLE (systemic lupus erythematosus) patient's response to therapy; may predict disease flare in SLE; evaluate for complement component deficiency; evaluate complement activity in cases of immune complex disease, glomerulonephritis, rheumatoid arthritis, SBE, cryoglobulinemia. The CH50 assay mainly evaluates the classical pathway.
Special Instructions
The test includes quantitation of total functional serum complement. Additional time may be required for confirmatory or reflex tests. Separate frozen specimens should be submitted for each test to avoid delays. Samples susceptible to degradation, like those not properly frozen, may lead to rejection or delayed turnaround.
Limitations
CH50 can be used to assess the integrity of the classical pathway (the presence of complement components C1-C9), but it cannot be used as a sensitive test for in vivo fixation of complement. A normal CH50 level indicates all components C1 through C9 are present; however, specific complement components like C3 or C4 can be significantly lower than normal without affecting CH50 activity. Depletion of alternative factors is not detected, and individual component measurement may be needed.
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
LOINC Codes
- 4532-8
- 4532-8
Result Turnaround Time
2-4 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.5 mL
Container
Red-top tube or gel-barrier tube
Collection Instructions
Allow specimen to clot at room temperature for 15 to 30 minutes, remove serum after centrifugation, place in plastic transport tube and freeze.
Storage Instructions
Freeze.
Causes for Rejection
Specimen not frozen; gross lipemia; plasma specimen.
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 14 days |