Endocrine Abstracts

The use of LC–MS/MS quantitative methods in clinical and research laboratories is becoming a well established reality that may overcome specificity and accuracy limits of immunoassays. Nevertheless, among different LC–MS/MS methods an agreement on the values that are to be considered normal or pathologic has not been reached yet, and this is mainly due to differences in LC–MS/MS methods, to the poor or absent availability of reference material and to the selection and ethnicity of healthy subject. We developed and validated a simultaneous LC–MS/MS method for the measurement of cortisol, corticosterone, 11deoxycortisol, androstenedione, testosterone, 17-OH progesterone, dehydroepiandrosterone and progesterone in serum and we proved the accuracy of the method against GC–MS certified material for cortisol, testosterone, 17-OH progesterone and progesterone, while no reference material is available for the other steroids. After given informed consent, 423 Caucasian healthy, normal weight (BMI≤25.0) and drug free subjects, age 18–90, were recruited among blood donors and among volunteers selected by telephonic interview. Blood withdrawal was between 0800 and 1000 h in non stressed conditions. We estimated non parametric reference intervals as the 2.5th and the 97.5th centiles in 4 age groups in males (18–25; 26–40; 41–60; >60) and in 6 age/fertility groups in females (18–25; 26–54 premenopausal; 18–54 follicular phase (day 1–10); 45–60 postmenopausal; >60). We found a general tendency for androgens to decrease with age mostly after age 40 for testosterone and androstenedione, to a greater extent in females compared to males. In both sexes, dehydroepiandrosterone has the highest rate of decrease, being its median concentration halved after age 40 compared to the youngest group. Our LC–MS/MS method generated with proper reference intervals is now ready to be applied to the study of specific endocrine dysfunctions.