The application of capability indices in the validation of ELISA methodology

Aim: To investigate the impact of sample replication number (duplicate vs triplicate) on the validation of ELISA methodology. Materials & methods: The methodology was validated with reference sample and test sample as an 11-point triplicate dilution series. The data were reanalyzed post-validation as if conducted as a duplicate dilution series. Results: The triplicate methodology was validated with a precision of 5.3% and mean bias of -1.7%. The duplicate methodology generated a precision of 5.7% and mean bias of -2.2%. Conclusion: Both the triplicate (method capability index = 1.37) and duplicate (method capability index = 1.25) ELISA methodology can support an 80-125% relative potency specification with a 0.004% or 0.018% probability of out-of-specification results, respectively.