Decreased concentrations of both C3 and C4 suggest activation of the classical pathway, whereas decreased concentration of just C3 suggests activation of the alternative pathway. Both complement factors may be used to monitor activity of patients with systemic lupus erythematosus (SLE) and immune complex-induced vasculitis.
No special preparation is needed for C3 / C4 Complement Ratio Blood. Inform your doctor if you are on any medications or have any underlying medical conditions or allergies before undergoing C3 / C4 Complement Ratio Blood. Your doctor depending on your condition will give specific instructions.
| Gender | Age groups | Value |
| UNISEX | All age groups | 88 - 252 mg/dl |
| UNISEX | All age groups | 12 - 75mg/dl |