Can Measurement of Progesterone, Estradiol, and Prolactin by Immunoassay be Interchanged? A Comparison of the Roche Cobas e601 vs. Abbott Architect i2000sr

Progesterone is a reliable indicator of either natural or induced ovulation, and it plays an important role in preparing for implantation in the uterus and maintaining pregnancy. Estradiol is the most powerful natural estrogen in humans. It adjusts reproductive function in females and, with progesterone, maintains a pregnancy. Prolactin is also an important indicator, and its major physiological action is the initiation and maintenance of lactation in women. Architect i2000sr and Cobas e601 are automated immunoassay systems that are widely used to measure progesterone, estradiol, and prolactin concentrations in the blood. However, there is a dearth of confidence in these methods for comparative research. Therefore, the aim of this study is to investigate the correlation of serum progesterone, estradiol, and prolactin results measured with Architect i2000sr and Cobas e601.Two hundred venous blood samples from routine serum progesterone, estradiol, and prolactin tests were analyzed on the Cobas e601 and the Architect i2000sr in our laboratory within the same day. Passing-Bablok regression analysis and a Bland-Altman plot were used to compare methods.According to the concordance correlation coefficient, the correlation was strong in estradiol, but the correlation of prolactin and progesterone was poor between the two systems. The Bland-Altman plots showed that the measured value of progesterone, estradiol, and prolactin detected by Cobas e601 were about 1.30, 1.24, and 1.10 times higher, respectively, than that measured using Architect i2000sr.The results of progesterone, estradiol, and prolactin of one method should not be directly transferable to the other.