Chemiluminescence immunoassay versus radioimmunoassay for the measurement of reproductive hormones.

OBJECTIVES

To compare the hormonal values determined by chemiluminescence immunoassay (CIA) and radioimmunoassay (RIA).

METHODS

Blood samples, drawn from eight volunteers during one menstrual cycle, were assayed for estradiol, progesterone, luteinizing hormone (LH), follicle stimulating hormone (FSH) and prolactin by CIA and RIA methods. The values obtained from these two assay techniques were compared. Statistical analysis were performed using the t-test, Pearson correlation coefficient and simple linear regression analysis.

RESULTS

CIA yielded lower mean values of LH, FSH, progesterone, but higher mean values of prolactin than RIA. Mean estradiol levels assayed by the two methods were similar. There was a good correlation between the hormonal values performed by the two methods. By calculation, the CIA hormonal value could accurately predict the RIA value by 96.6, 93.9, 89.9 and 66.0% for progesterone, LH, FSH and prolactin, respectively.

CONCLUSIONS

The disparity in the hormonal values obtained from different assay methods warrants clinicians to be aware of their clinical interpretation. Using the same reference range for different assay methods is not appropriate. A comparative study between the new and standard assays is essential.