2019 Volume 3 Issue 1 Pages 19-29
Application of liquid chromatography tandem mass spectrometry (LC-MS/MS) in clinical chemistry has been increasing worldwide, especially in large institution and reference laboratories. Although immunoassays are often used for measurement of serum estradiol (E2) when fast turnaround time is required, more sensitive and specific measurements are needed for determination of menopausal status, estrogen deficiency and in the diagnosis of sex hormone related disorders. Furthermore, simultaneous measurement of estrone (E1) and E2 is often requested particularly from gynecologic oncologists. Indeed, increased risk of endometrial cancers has been shown in subjects with high serum estrogen levels. The aim of this study is to develop and validate LC-MS/MS method for simultaneous measurement of E1 and E2 in human serum. Serum samples were first prepared in a 96-well supported liquid extraction plate and the eluate was derivatized by the dansyl chloride acetone solution. The derivatized samples were subjected to LC-MS/MS, and detected by selected reaction monitoring. The lower limits of quantification for E1 and E2 were 6.2 and 7.3 pg/mL, respectively. The 60 female sera values obtained by the LC-MS/MS method were compared with those obtained by two commercially available immunoassays. The both of values obtained by the two immunoassays exhibited positive bias particularly at low E2 levels. Various preanalytical factors, such as long sample sitting prior to serum separation, repeated freeze–thaw cycles, and the presence of anticoagulants, had no significant effects on these determinations. This method will aid further understanding of low-abundance estrogen, as well as the accurate determination of E1 and E2.
