C5a Level By RIA
Test Code
C5AR
Description
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 C5a can be elevated above normal levels in many conditions associated with inflammation, including infection, asthma, sepsis, and renal diseases (IgA nephropathy, C3 glomerulonephritis) as well as immune complex diseases such as cold agglutinin-mediated autoimmune hemolytic anemia.
Collect
Plasma from a lavender top (EDTA) tube is the only acceptable sample type. Mix sample thoroughly. Keep tubes cold on wet ice or with a cold pack after collection.
Patient Prep
Within 30 minutes of venipuncture, centrifuge the collection tube at 1600(±200) x g (rcf) at 4°C (± 2°C) for 15 (± 1) minutes. Transfer the cell-free plasma to a clean tube and immediately store samples at -20°C, or freeze at -60°C or below in an ultra-low freezer.
Preferred volume: 1 mL
Ambient temperature for centrifugation is acceptable provided that the time between collection and storage is minimized (approximately 30 minutes).
Pediatric Collection
Minimum volume: 0.5 mL plasma, frozen.
Unacceptable Conditions
Thawed specimen.
Storage Transport Temp
Send frozen plasma Priority Overnight via FedEx and in a well insulated container on dry ice.
Stability
-60°C or below in an ultra-low freezer - up to 2 years
Performed
Monday - Friday
Methodology
Radioimmunoassay (RIA)
Turnaround Time
up to 4 weeks
Department
Complement Lab
Synonyms
AP (C5ades Arg Level), Radial Immuno Assay ( (C5ades Arg Level)), C5 anaphylatoxin (C5ades Arg Level), C5a anaphylatoxin, Complement (C5ades Arg Level), CP (C5ades Arg Level), C5a des Arg Level, complement derived chemotactic factor (C5ades Arg Level), C5AL
Study Offerings
Not offered
Reference Interval
4.7-9.5 ng/mL
Interpretation
Elevated C5a levels are indicative of classical, alternative and/or lectin pathway activation.CPT Code
86160
New York Approved
Legacy
FDA
LDT