Objective To analyse the factors influencing the differences of the internal control( IC) test results in the COBAS s201 blood screening of nucleic acid amplification technology( NAT),and to discuss the usages of IC values for stability of detection system. Methods according to different instruments( A and B instrument),different reagent lots( Lot1,Lot2 and Lot3) and different specimen types( MPV,HIV-1O,HIV-2,NC and donor samples),the IC values of the results from 131 batches of NAT selected randomly in the...