Kaiser Permanente Capitol Hill Medical Center

Objectives Recently, an estradiol immunoassay manufacturer (Beckman Coulter, USA) issued an ‘important product notice’ alerting clinical laboratories that their assay (Access Sensitive Estradiol) was not indicated for patients undergoing exogenous estradiol treatment. The objective of this analysis was to evaluate immunoassay bias relative to liquid chromatography tandem mass spectrometry (LC-MS/MS) in transgender women and to examine the influence of unconjugated estrone on measurements.Design Cross-sectional secondary analysis.MethodsEstradiol concentrations from 89 transgender women were determined by 3 immunoassays (Access Sensitive Estradiol (‘New BC’) and Access Estradiol assays (‘Old BC’), Beckman Coulter; Estradiol III assay (‘Roche’), Roche Diagnostics) and LC-MS/MS. Bias was evaluated with and without adjustment for estrone concentrations. The number of participants who shifted between three estradiol concentration ranges for each immunoassay vs LC-MS/MS (>300 pg/mL, 70–300 pg/mL, and <70 pg/mL) was calculated.ResultsThe New BC assay had the largest magnitude overall bias (median: −34%) and was −40%, −22%, and −10%, among participants receiving tablet, patch, or injection preparations, respectively. Overall bias was −12% and +17% for the Roche and Old BC assays, respectively. When measured with the New BC assay, 18 participants shifted to a lower estradiol concentration range (vs 9 and 10 participants based on Roche or Old BC assays, respectively). Adjustment for estrone did not minimize bias.ConclusionsImmunoassay measurement of estradiol in transgender women may lead to falsely decreased concentrations that have the potential to affect management. A multidisciplinary health care approach is needed to ensure if appropriate analytical methods are available.

Transgender women and nonbinary people seeking feminizing therapy are often prescribed estrogen as a gender-affirming hormone, which will alter their reproductive hormone axis. Testosterone, estradiol, and other reproductive hormones are commonly evaluated to assess therapy, but reference intervals specific to transgender women have not been established. The objective of this study was to derive reference intervals for commonly measured analytes related to reproductive endocrinology in a cohort of healthy gender nonconforming individuals on stable feminizing hormone therapy. Healthy transgender individuals who had been prescribed estrogen (n = 93) for at least a year were recruited from internal medicine and primary care clinics that specialize in transgender medical care. Total testosterone and estradiol were measured using immunoassay and mass spectrometry; LH, FSH, sex hormone binding globulin, prolactin, progesterone, anti-mullerian hormone (AMH), and dehydroepiandrosterone sulfate (DHEAS) were measured using immunoassay; free testosterone was calculated. Reference intervals (central 95%) were calculated according to Clinical Laboratory Standards Institute guidelines. The distribution of results for transgender women was different than what would be expected from cisgender men or women across all measurements. Use of spironolactone was associated with changes in the result distribution of AMH, FSH, LH, and progesterone. Compared to liquid chromatography coupled to tandem mass spectrometry (LC/MS/MS), immunoassay was sufficient for the majority of estradiol and total testosterone measurements; free testosterone added little clinical value beyond total testosterone. Reference intervals specific to transgender women should be applied when evaluating reproductive endocrine analytes. Spironolactone is a significant variable for result interpretation of some tests.

The approaching four hundredth anniversary of the publication of the 1559 edition of John Calvin's Institutes of the Christian Religion has aroused in Spanish-speaking circles a desire to make more generally available the translation made by Cipriano de Valera in 1597. This labor of love has been undertaken by Professor B. Foster Stockwell in Buenos Aires and his facsimile reproduction of the Spanish translation of the Institutes is being published by La Aurora press.