The analytical and clinical performance of a commercial automated immunoassay system (Immulite®) for estradiol (E2) in serum was evaluated. The functional sensitivity for E2 was 0.07 nmol/l, and ...analytical imprecision (<13 %, <9 % and <7 % at 0.22, 0.51 and 1.51 nmol/l, respectively) for concentrations above this detection limit met published analytical goals. The assay recovery was good and the assay was linear over a wide concentration range. No sample carryover was found, and interferences from common substances present in serum were observed only at very high concentrations. Most of samples from men and postmenopausal women showed E2 concentrations below the detection limit. Longitudinal estradiol profiles from 11 healthy menstruating women showed characteristic menstrual cycle patterns (12 samples per subject obtained during a 30-day period). Longitudinal studies on women during induction of ovulation showed that E2 concentrations are highly correlated with the total number of follicles. Our results demonstrate the reliability of this system for routine use in the clinical laboratory.
We evaluated the technical performance of the Ciba Corning ACS:180 automated immunoassay system for the following analytes: thyroid-stimulating hormone, free thyroxine, luteinizing hormone, ...follicle-stimulating hormone, prolactin, human chorionic gonadotropin, carcino-embryonic antigen, and prostate-specific antigen. The characteristics evaluated were: precision, carryover, linearity, lower limit of detection, analytical interferences, and comparison with other methods. Satisfactory results were obtained in the within-run and between-run precision studies. Neither sample nor reagent carryover was found for any assay. The range of linearity was acceptable. For some of the assays evaluated, the lower limit of detection was better than that claimed by the manufacturer. Correlation between ACS:180 methods and compared methods was adequate. We conclude that the ACS:180 offers good reliability, practicability, and performance capabilities.
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.
