In vitro effect of dipyrone on several peroxidase labelled immunoassays

We studied the in vitro effect of dipyrone on the determination of free triiodothyronine (free T3), cortisol, progesterone, estradiol, carcinoembryonic antigen, human chorionic gonadotropin and alpha-fetoprotein measured with an immunoenzyme assay based on enhanced luminescence that uses peroxidase as label. We found significant interference from dipyrone (p < 0.01) in the determination of all the analytes mentioned: for progesterone and estradiol the interference was present at high doses of dipyrone; for free T3 and cortisol the minimum dipyrone concentration producing interference was 712 mumol/l and for carcinoembryonic antigen, human chorionic gonadotropin and alpha-fetoprotein 44 mumol/l. Dipyrone has an analytically and statistically significant interference effect on the determination of the mentioned analytes.