Lab Test

Complement, C3

C3, C3 Complement

Test Codes

Antrim #30205, EPIC: LAB6456, C3

Department

Chemistry

Specimen Collection Criteria

Collect: One Gold-top SST tube.

Physician Office/Draw Specimen Preparation

Let specimen clot 30-60 minutes then immediately centrifuge to separate serum from cells. Refrigerate (2-8°C or 36-46°F) the centrifuged collection tube within twelve hours of collection.

Preparation for Courier Transport

Transport: Centrifuged collection tube, refrigerated (2-8 °C or 36-46 °F). (Minimum: 0.5 mL)

Rejection Criteria

  • Grossly lipemic specimens.
  • Hemolyzed specimens
  • Plasma specimens.
  • Specimens that have gross bacterial contamination.
  • Specimens not collected and processed as indicated.

In-Lab Processing

Let specimen clot 30-60 minutes then immediately centrifuge to separate serum from cells. Deliver immediately to the appropriate testing station.

Storage

Specimen Stability for Testing:

Centrifuged SST Tubes and Microtainers® with Separator Gel
Room Temperature (20-26°C or 68-78.8°F): 12 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): Unacceptable

Red-top Tubes and Microtainers® without Separator Gel
Room Temperature (20-25°C or 68-77°F): 12 hours
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Serum Specimens (Pour-Overs)
Room Temperature (20-26°C or 68-78.8°F): 12 hours
Refrigerated (2-8°C or 36-46°F): 7 days
Frozen (-20°C/-4°F or below): 3 months

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days

Laboratory

Dearborn Chemistry Laboratory

Royal Oak Automated Chemistry Laboratory

Performed

Sunday – Saturday, 24 hours a day.
Results available within 24 hours.

Reference Range

82-193 mg/dL.

Test Methodology

Immunoturbidimetric.

Interpretation

  • Increased C3 levels are found in many acute inflammatory diseases.
  • Decreased C3 levels are associated with genetic deficiency, systemic lupus erythematosus, glomerulonephritis, liver disease, subacute bacterial endocarditis, hemolytic anemia. autoimmune disease, neonatal respiratory distress syndrome, bacteremia, tissue injury and chronic hepatitis.

Clinical Utility

C3 quantitation is used to detect individuals with congenital C3 deficiencies, or individuals who have depleted their complement levels due to an immunological process. C3 has the highest serum concentration of any complement component. Complement C3 is used as a screening test because it is consumed by activation of either the classical or alternative pathway. Individual assays for C3 and C4 are most useful in monitoring patients with immunologic diseases. Functional assays (e.g., the CH50 test) measure the activity of the entire complement cascade and are more likely to detect inherited deficiencies.

CPT Codes

86160
LOINC: 4485-9

Contacts

Last Updated

5/5/2021

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