Complement, total alternative pathway
The AP50 assay measures the ability of serum complement components to form membrane attack complex, which can be detected by ELISA. C3 and C4 levels must also be requested. The assay is used as a screening test for defects of individual components of the alternative and terminal pathways. It should not be used for monitoring complement consumption, instead request C3 and C4 levels.
Suspected complement deficiency
50-125 % of normal
|Sample & container required||RST (rust top) Separate and freeze immediately Transport frozen|
|Sample volume||5-10 mL (1 mL serum)|
|Turnaround time||21 days|