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HelpCatalog ID C4 Comp C4 Complement
CPOE Test Name
C4 Complement
Epic EAP Test Code
LAB151
Specimen Type
Serum
Specimen Requirements
gold top SST tube
Causes for Rejection
Improper labeling; gross lipemia; wrong tube; insufficient quantity
CPT / HCPCS Code
86160
Performing Lab
Core Laboratory, AD 3301
Reference Values
19 - 52 mg/dL
Storage and Transport
Refrigerated at 2-8C: up to 8 days
Frozen </= -20C: up to 3 months
Sample should be refrigerated or stored if assay cannot be run within 4 hours
Interpretation
The Complement system is composed of a series of circulating blood proteins that serve as mediators of the inflammatory response. C4 is utilized only by the classical complement pathway, so that it is decreased only when this pathway is activated. In diseases activating the alternate pathway only, C4 levels will be normal. Measurements of this protein aids in the diagnosis of immunologic disorders, especially those associated with deficiencies of complement components.