**Note: All laboratory testing requires an authorizing physician. DHA Laboratory offers a Patient Direct Program that partners you with an authorizing physician. If you have any additional questions regarding the availability of testing, please contact our laboratory by telephone or email.**
The testing for C4a can help determine if a deficiency or abnormality is a contributing factor to increased infections or increased autoimmune activity. The measurement can also be used to monitor autoimmune disorders. C4a, in conjunction with C3a, may be useful markers in acute and chronic Lyme disease.
Patient Preparation: No radioactive isotopes administered within 48 hours prior to venipuncture.