| Test Name: |
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Complement C4
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| Test Code(s): |
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C4 / XC4
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| CPT Code(s): |
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86160
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| Methodology: |
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Nephelometry
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| Clinical Significance: |
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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.
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| Days Performed: |
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Daily, 24 hours.
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| Turnaround Time: |
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Stat: 1 hour.
Routine: 4 hours.
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Specimen Requirements
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| Specimen: |
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Blood
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| Collection Container: |
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Preferred: Red cap with yellow ring (SST)
Also Acceptable:
Green cap with yellow ring (PST),
Green top,
Red top
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| Collection Volume: |
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Preferred: 4 mL
Pediatrics: 0.4 mL
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| Sample Analyzed: |
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Serum or plasma
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| Volume Required: |
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Preferred: 0.5 mL
Pediatrics: 0.2 mL
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| Specimen Processing: |
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Centrifuge. If a complete barrier has not formed, transfer cell-free serum/plasma to plastic vial. Refrigerate.
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| Specimen Transport: |
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Transport specimen to UWHC Core Laboratory (B4/220). Transport with coolant pack if coming from outreach location.
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| Unacceptable Criteria: |
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Grossly hemolyzed, lipemic and turbid specimens are not acceptable.
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| Stability: |
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Ambient: 8 hours
Refrigerated: 4 days
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Interpretation
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Reference Interval:
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| 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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