SIMPLE PROCEDURES CAN MARKEDLY ENHANCE AUTOMATED IMMUNOASSAY PERFORMANCE

Theoretically, optimal performance for an immunoassay system is achiev ed when both the interassay and within-run precisions are identical. U sing the Ciba Coming ACS:180(TM) automated immunoassay system, the aut hors made two simple changes to the operating procedures that allowed near-optimal analytic performance (as assessed with the interassay coe fficient of variation determined by the protocol of the National Commi ttee for Clinical Laboratory Standards) for four of six hormones: thyr oid-stimulating hormone, luteinizing hormone, prolactin, and human cho rionic gonadotropin. At low hormone concentrations, the 20% interassay coefficients of variation for the hormones assayed were as follows: f ree tetraiodothyronine, 1.74 pM; thyroid-stimulating hormone,.033 mIU/ L; luteinizing hormone, .21 U/L; follicle-stimulating hormone, .69 U/L ; prolactin, 5.03 mU/L; and human chorionic gonadotropin, 1.52 mU/L. T he operational enhancements improved the analytic performance of the a ssay for all hormones assessed compared with the performance of previo usly used isotopic immunoassays.