C4
Test:
451
CPT:
86160
Synonyms
Complement C4,
C4
C4 (β1E Globulin)
C4 Complement
Fourth Complement Component
Special Instructions
Expected Turnaround Time
1 – 2 days
Specimen Requirements
Specimen
1 – 2 days
Volume
1 mL (adult), 0.5 mL (pediatric)
Minimum Volume
Container
Red-top tube, gel-barrier tube, green-top (lithium heparin) tube, or lavender-top (K3-EDTA) tube
Collection
Allow serum to clot at room temperature for 15 to 30 minutes. Remove serum or plasma after centrifugation and transfer to a plastic transport tube.
Storage Instructions
Maintain specimen at room temperature.
Causes for Rejection
Excessive lipemia (>250 mg/dL) and rheumatoid factors (>200 IU/mL) significantly increase the apparent C4 concentration.
Test Details
Use
Quantitation of C4 is used to detect individuals with inborn deficiency of this factor or those with immunologic disease in whom hypercatabolism of complement causes reduced levels. These diseases include lupus erythematosus, serum sickness, certain glomerulonephritides, chronic active hepatitis, and others.