EStradiol and PRogesterone in In vitro ferTilization (ESPRIT): a multicenter study evaluating third- versus second-generation estradiol and progesterone immunoassays.

PURPOSE: To assess estradiol (E2) and progesterone levels during ovarian stimulation determined by third-generation (Gen III) and second-generation (Gen II) Elecsys® immunoassays. METHODS: E2 and progesterone concentrations were measured using Elecsys® Gen III and Gen II immunoassays, and progesterone concentrations on the day of ovulation triggering were determined by LC-MS/MS. This was a retrospective, non-interventional study conducted at European tertiary referral infertility clinics in women aged 18-45 years, with a body mass index 18-35 kg/m2, regular menses, and both ovaries. RESULTS: Serum samples were obtained from 230 women classified by oocyte retrieval as poor (33.0%; 0-3 oocytes), normal (40.9%; 4-15 oocytes), or high (26.1%; > 15 oocytes) responders. E2 and progesterone levels increased during ovarian stimulation, with greatest increases observed in high responders. Elecsys® Gen III and Gen II assay results were highly correlated for E2 (Pearson's r = 0.99) and progesterone (r = 0.89); Gen III results were lower than Gen II for both E2 and progesterone. On the day of triggering, Gen III E2 and progesterone levels showed a difference of - 15.0% and - 27.9%, respectively. Progesterone levels (on day of triggering) measured by LC-MS/MS correlated better with Gen III (0.98) than Gen II (0.90). Mean relative differences for Gen III and Gen II assays versus LC-MS/MS were 14.6% and 62.8%, respectively. CONCLUSION: E2 and progesterone levels determined with Elecsys® Gen II and III assays were highly correlated; results were lower for Gen III versus Gen II. Differences observed for progesterone on the day of triggering may be clinically relevant.

Correction to: EStradiol and PRogesterone in In vitro ferTilization (ESPRIT): a multicenter study evaluating third­ versus second­generation estradiol and progesterone immunoassays.

The article "EStradiol and PRogesterone in In vitro ferTilization (ESPRIT): a multicenter study evaluating third­ versus second­generation estradiol and progesterone immunoassays.

Parathyroid hormone reference ranges in healthy individuals classified by vitamin D status.

PURPOSE: Parathyroid hormone (PTH) concentrations are routinely measured in the diagnosis and management of bone and kidney diseases, but reference ranges can be overestimated if determined in otherwise healthy individuals for whom vitamin D deficiency was not evaluated. We establish PTH reference ranges in apparently healthy, normocalcemic, normophosphatemic individuals categorized by 25-hydroxyvitamin D (25(OH)D) status using the Elecsys® PTH (cobas e 601) and Elecsys® Vitamin D total II electrochemiluminescence immunoassays (cobas e 411). METHODS: This prospective, non-interventional study measured PTH in serum from 653 apparently healthy adults [56.7% female; 68.2% white/Caucasian; 28.6% African American; median age 44 years (range 21-83)] from three diverse geographic sites across the USA during summer and winter months. Subjects were classified by concomitant vitamin D sufficiency (≥ 30 ng/mL), insufficiency (> 20 to < 30 ng/mL) or deficiency (≤ 20 ng/mL). RESULTS: In vitamin D sufficiency, median PTH was 31.9 pg/mL [range (2.5th-97.5th percentile) 17.9-58.6] compared with 35.5 pg/mL (17.0-60.4) for insufficiency, and 39.8 pg/mL (19.5-86.4) for deficiency. A significant inverse relationship was found between PTH and 25(OH)D (P < 0.001). After accounting for vitamin D, potential effects of race or season as covariates were relatively small or absent. CONCLUSIONS: Upper reference limits (URL) for PTH in vitamin D sufficiency/insufficiency were similar and lower than current values. Clinically important PTH elevations were observed in vitamin D deficiency, where revised reference ranges with a higher URL may be appropriate. These data may help to distinguish vitamin D-related PTH elevations from other causes [e.g., primary (normocalcemic) or secondary hyperparathyroidism].