C4d Fragment, EIA

For Specimen Integrity during Extreme Weather see the “Lockbox Usage in Extreme Weather” document at the top of this page.

Test Code

CPT Codes

Preferred Specimen
1 mL frozen plasma collected in an EDTA (lavender-top) tube

Minimum Volume
0.2 mL

Transport Temperature

Specimen Stability
Room temperature: Unacceptable
Refrigerated: 4 hours
Frozen: 14 days

Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Hemolysis • Serum • Gel barrier interferes with assay methodology

Enzyme Immunoassay (EIA)

FDA Status
This test was performed using a kit that has not been cleared or approved by the FDA. The analytical performance characteristics of this test have been determined by Quest Diagnostics. This test should not be used for diagnosis without confirmation by other medically established means.

Setup Schedule
Tuesday Night Report available: 4 Days

Reference Range
0.9-8.0 mcg/mL

Clinical Significance
Clinical use is to exclude known rheumatoid arthritis, systemic lupus erythematosus, and chronic uticaria with hypocomplementemia. C4d is a stable activation product of C4 cleavage, and is useful to determine classical pathway complement activation.

Performing Laboratory
Quest Diagnostics Nichols Institute-San Juan Capistrano, CA
33608 Ortega Highway
San Juan Capistrano, CA 92675-2042

Last Updated: November 24, 2021

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.