C3 Complement

Test Code

Alias/See Also

Epic: LAB152

Preferred Specimen

Specimen Type: Serum
Collection Container: Serum gel
Specimen Volume: 3 mL

Minimum Volume

0.25 mL

Instructions

Centrifuge and separate cells after clot formation and within 4 hours of collection

Transport Container

Plastic vial

Specimen Stability

Room temperature: Unacceptable
Refrigerated: 8 days
Frozen: 8 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)

Unlabeled, mislabeled, wrong tube type, hemolyzed, visually lipemic, QNS, exceeds specimen/stability requirements.

Methodology

Immunoturbidimetric

Setup Schedule

Daily

Report Available

Same day

Limitations

Samples containing paraproteins (abnormal monoclonal antibodies) may incorrectly fall within the reference range. Samples with elevated total protein concentrations or suspected paraproteinemia can be screened with other methods such as electrophoresis. Turbidity and particles in samples can interfere with the assay. Therefore, particulate matter should be removed by centrifugation prior to running the assay.

Reference Range

Male
1 - 14 years: 80 - 170 mg/dL
>14 years: 82 - 185 mg/dL

Female
1 - 14 years: 82 - 173 mg/dL
>14 years: 83 - 193 mg/dL

Clinical Significance

The Complement system is an integral part of the immune defenses. Increased C3 levels are associated with acute phase reaction, rheumatic disease, viral hepatitis, myocardial infarction, cancer, diabetes, pregnancy, sarcoidosis, amyloidosis, thyroiditis, inflammatory bowel disease, typhoid fever, and pneumococcal pneumonia. Decreased levels occur in individuals with congenital deficiency or immunologic diseases, particularly SLE, infective endocarditis and DIC. The role of C3 in complement pathways results in patients with decreased levels being at risk for severe infection, particularly S. pneumoniae, H. influenzae and N. meningitis.

Performing Laboratory
Inova Laboratories
2832 Juniper Street
Fairfax, VA 22031

Last Updated: March 6, 2023
Last Review: N. Wolford, March 6, 2023

The CPT Codes provided in this document are based on AMA guidelines and are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payor being billed. Any Profile/panel component may be ordered separately. Reflex tests are performed at an additional charge.