Access estradiol assay

Serum total cholesterol, triglyceride, low-density lipoprotein cholesterol (LDL), high-density lipoprotein cholesterol (HDL), fasting glucose, estradiol and follicle-stimulating hormone (FSH) were measured using standard procedures at the Department of Laboratory Medicine, Changhua Christian Hospital. Brief, the levels of estradiol and FSH were measured in frozen plasma specimens using the Access Estradiol assay and the Access hFSH assay on the Beckman Access Immunoassay system with a dynamic range of ≥ 3.5 logs (Beckman Coulter, Fullerton, CA.). Values for estradiol were reported as pg/ml and those for FSH were reported as mIU/mL. The lower limit value of detection was 20 pg/ml for estradiol and was 0.2 mIU/mL for FSH, respectively. The samples of estradiol and FSH were run undiluted. None of the others were outside the linear-range detection of standard curve. All samples were analyzed in duplicates. For quality control purposes, two duplicates of commercial control samples were tested on each microplate in any given run. The interassay and intraassay laboratory coefficients of variation (CVs) were < 8% and 8.6% for estradiol, respectively, and were < 8% and 5.6% for FSH, respectively. Insulin resistance was assessed based on the homeostatic model assessment of insulin resistance (HOMA-IR) using the following formula: [fasting glucose (mmol/L) × insulin (μU/L)/22.5].

The concentrations of follicle-stimulating hormone (FSH) and estradiol were measured according to the standard procedures of the Department of Laboratory Medicine, Changhua Christian Hospital. Briefly, we measured FSH and estradiol in plasma specimens using the Access hFSH Assay and the Access Estradiol Assay, respectively, on the Beckman Access Immunoassay System (Beckman Coulter, Fullerton, CA, USA). The unit measurement of FSH and estradiol was mIU/mL and pg/ml, respectively. For estradiol, the inter- and intra-assay laboratory coefficients of variation were less than 8% and 8.1%, respectively, and for FSH, they were less than 8% and 6%, respectively. We measured the levels of high-sensitivity C-reactive protein (hs-CRP) and total cholesterol (including low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and triglycerides (TG)) using an automatic lab instrument at the Department of Laboratory Medicine, Changhua Christian Hospital.