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C4a Level Testing

Complement Molecule

The complement system is part of our innate immune response. It is vital to our defense against invasive microorganisms. Activation of 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.

National Jewish Health Advanced Diagnostic Laboratories offers an 125I C4a Des Arg Radioimmunoassay to provide highly accurate measurements of C4a in human plasma. The assay includes pre-processing to remove full-length C4 from the sample and reduce cross-reactivity, providing a cleaner signal and more accurate assessment of C4a levels in the body. Elevated C4a levels can be associated with inflammatory and autoimmune conditions including chronic fatigue syndrome, multiple sclerosis, lupus, as well as being an early marker for acute Lyme disease.

About the C4a Level RIA Test

  • Accurate measurement of C4a plasma levels
  • Reduced risk of cross-reactivity with intact C4
  • 7-10 business day turnaround time
  • Stable for 4 weeks at -20 °C, or up to 2 years at -70 °C


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Questions? Call 303.398.1669 or email clinreflabs@njhealth.org to speak with a client services representative.