Complement Level C4
A critical element for activation of classical pathway is C4. Patients suffering from SLE, Immune complex disease and hereditary angioedema are found to have decreased levels of C4. Congenital deficiency of it can lead to increased risk of recurrent bacteremia especially S.pneumoniae. This evaluation helps in diagnosis of C4 deficiency and also for investigating patient with an undetectable Total complement level.
How to prepare for the test?
Overnight fasting is compulsory.