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UW Health SMPH
American Family Children's Hospital

UW Hospital and Clinics Lab Test Directory

Test Name: Complement C4

Test Code(s): C4 / XC4

CPT Code(s): 86160

Methodology: Nephelometry

Clinical Significance: Complement levels are requested in the following clinical situations: workup for immunodeficiency, assessment of SLE, assessment of disease activity in SLE, assessment of vasculitis (including glomerulonephritis) and assessment of disease activity in vasculitis.

Days Performed: Daily, 24 hours.

Turnaround Time: Stat: 1 hour.
Routine: 4 hours.

Specimen Requirements

Specimen: Blood

Collection Container: Preferred: Red cap with yellow ring (SST)
Also Acceptable: Green cap with yellow ring (PST), Green top, Red top

Collection Volume: Preferred: 4 mL
Pediatrics: 0.4 mL

Sample Analyzed: Serum or plasma

Volume Required: Preferred: 0.5 mL
Pediatrics: 0.2 mL

Specimen Processing: Centrifuge.  If a complete barrier has not formed, transfer cell-free serum/plasma to plastic vial.  Refrigerate.

Specimen Transport: Transport specimen to UWHC Core Laboratory (B4/220). Transport with coolant pack if coming from outreach location.

Unacceptable Criteria: Grossly hemolyzed, lipemic and turbid specimens are not acceptable.

Stability: Ambient: 8 hours
Refrigerated: 4 days


Reference Interval:
 Age:  mg/dL
 0 days - 3 months            8-40
 4 months - 12 months  10-55
 13 months - 4 years  12-50
 5 years - 17 years  12-45
 18 years and up  10-40





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