C4a is an inflammatory marker that is variably elevated in Chronic Lyme Disease patients.
Same old story: if C4a is elevated, it is a useful marker of disease and correlates with symptoms; if it is normal, not very useful but probably a better prognosis for the patient.
The test is available through National Jewish Medical Center in Denver. It can be ordered as a send-out from Bioreference or Quest.
Labcorp will not do it because they have their own version that is worthless.
Last Updated- February 2020