C2 Complement, Functional, Serum
Use
The test is useful for investigating patients with a low (absent) hemolytic complement to assess the functionality of C2. C2 is a part of the classical pathway of the complement system, which is critical in immune response through opsonization, which facilitates phagocytosis, and formation of the membrane attack complex that leads to cell lysis. C2 deficiency, though rare, is the most common inherited complement deficiency associated with autoimmune diseases like systemic lupus erythematosus.
Special Instructions
The total complement assay should be used as a preliminary screen for suspected complement deficiencies before ordering individual complement component assays. Patient preparation includes fasting for 12 hours, though it is preferred but not required.
Limitations
Proper handling and processing of specimens are crucial to avoid pre-analytical activation of the complement system. Gross hemolysis and gross lipemia are causes for rejection due to potential interference with the assay. The absence of early complement components prevents the immune complexes from activating the cascade, leading to deficiencies in generating lytic activity or clearing immune complexes.
New York Approved
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
LOINC Codes
- 93977-7
- 93977-7
- 69048-7
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 the tube on wet ice and allow it to clot. Centrifuge at 4°C, aliquot serum into a plastic vial, and freeze within 30 minutes of centrifugation. Specimens must be placed on dry ice if not frozen immediately.
Patient Preparation
Fasting: 12 hours, preferred but not required
Causes for Rejection
Gross hemolysis, Gross lipemia
Stability Requirements
| Temperature | Period |
|---|---|
| Frozen | 21 days |