26126 C4a Level by RIA (FC4AL)

The complement system is part of our innate immune response. It is vital to our defense against invasive microorganisms. Complement activation can occur through the classical, lectin and alternative pathway, which then converge to a common terminal pathway. Activation of the complement pathway(s) results in the generation of biologically active peptides, also known as complement split products, and referred to as anaphylatoxins (C4a, C3a, C5a) which protect us from invasive microorganisms by enhancing inflammation, facilitating the clearance of immune complexes and apoptotic cells, enhancing cellular and antibody immune responses and altering vascular permeability, as well as smooth muscle contractility.

The anaphylatoxin C4a can be elevated above normal levels in many conditions associated with inflammation, including chronic fatigue syndrome, multiple sclerosis, immune complex diseases such as antiphospholipid syndrome and autoimmune conditions such as lupus. C4a is also an early marker of acute Lyme disease.​

This test should be regarded as 'Research Use Only'. This test uses a kit/reagent designated by the manufacturer as for research use, not for clinical use. The performance characteristics for this test have been validated by National Jewish Health. It has not been cleared or approved by the U.S. Food and Drug Administration. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions. This laboratory is certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA-88) as qualified to perform high complexity clinival laboratory testing.

This test may not be covered by insurance and providers need to inform all patients of this prior to ordering. 

For Medicare patients, an Advanced Beneficiary notice (ABN) is required; for Medicaid patients, a Noncovered Services Waiver is required, and for commercial payers, prior authorization should be obtained.   ​​