C3 Complement, Functional, Serum
Use
This test is useful for the diagnosis of C3 deficiency and the investigation of a patient with an undetectable total complement level. Complement proteins, like C3, play a crucial role in the immune response by enabling opsonization and promoting the inflammatory response through pathways including the classical, alternative, and lectin pathways. Deficiency, although rare, may result in recurrent infections and has been implicated in autoimmune processes.
Special Instructions
The total complement assay should be used as a screening test for suspected complement deficiencies before ordering individual component assays. Proper specimen handling is critical, ensuring that the complement system is not activated before clinical testing.
Limitations
The test may not detect cases where the protein is present but nonfunctional or in lower quantities. Specimen handling must ensure that C3 inactivation does not occur during shipment. Absence or low C3 levels should be replicated with new specimens to confirm deficiency.
New York Approved
Methodology
Other (Turbidimetric Measurement)
Biomarkers
LOINC Codes
- 87723-3
- 87723-3
Result Turnaround Time
1-3 days
Related Documents
For more information, please review the documents below
Specimen
Serum
Volume
1 mL
Minimum Volume
0.5 mL
Container
Plastic vial
Collection Instructions
Immediately after collection, place on wet ice, allow to clot, centrifuge at 4°C, aliquot serum into plastic vial, and freeze within 30 minutes of centrifugation. Use dry ice if not frozen immediately.
Patient Preparation
Fasting for 12 hours is preferred but not required.
Storage Instructions
Freeze.
Causes for Rejection
Gross hemolysis and gross lipemia are grounds for rejection. Gross icterus is acceptable.
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 14 days |