Sunagawa Shawnalyn W, Winchester Lee C, Wichman Christopher S, Avedissian Sean N, Erikson David W, Kernan Molly, Marzinke Mark A, Mykris Timothy M, Nandakumar Renu, Nolin Thomas D, Podany Anthony T, West Raymond E, Chen Beatrice A, Chappell Catherine A, Scarsi Kimberly K
Antiviral Pharmacology Laboratory, College of Pharmacy, University of Nebraska Medical Center, Omaha, NE, USA.
Department of Biostatistics, College of Public Health, University of Nebraska Medical Center, Omaha, NE, USA.
Contraception. 2025 Feb;142:110720. doi: 10.1016/j.contraception.2024.110720. Epub 2024 Oct 2.
To compare performance characteristics of etonogestrel bioanalytical assays across laboratories.
We conducted a blinded, six laboratory study: five academic laboratories and one contracted commercial laboratory (reference). Etonogestrel was quantitated at each laboratory in both prepared serum and/or plasma samples of six known etonogestrel concentrations, and in 60 clinical samples from participants using etonogestrel-containing contraceptive methods. Per regulatory guidance, laboratory accuracy (percent bias) and precision (coefficient of variation; CV) were defined as ±15% of the nominal prepared concentration. We compared inter- and intra-laboratory agreement using a Kendall's Tau-B and Passing-Bablok regression.
For prepared samples, six laboratories analyzed serum and three laboratories analyzed plasma. All etonogestrel results were within ±15% for accuracy across all concentrations at four labs, including the reference laboratory. All labs demonstrated high precision, with only one occurrence of CV >15%. We found a positive association between prepared plasma and serum etonogestrel results (Kendall's Tau-B 0.80-0.88). For clinical samples, five laboratories analyzed serum and three laboratories analyzed plasma. Compared to the reference laboratory, inter-laboratory serum etonogestrel concentrations were positively correlated (Kendall's Tau-B 0.76-0.95). Proportional bias was observed, meaning individual lab etonogestrel results were consistently higher (slope estimates 0.78-0.95) or lower (slope estimates 1.05-1.10) than the reference laboratory. In clinical samples, intra-laboratory results were well associated between plasma and serum (Kendall's Tau-B 0.92-0.96).
There was good intra-laboratory agreement, irrespective of sample matrix; however, there was inter-laboratory variability in etonogestrel results. Differences between laboratory results should be considered when comparing etonogestrel pharmacokinetics across studies.
Etonogestrel concentrations were highly precise within each laboratory and were comparable between serum and plasma. Results varied between laboratories (5-28% higher to 5-9% lower compared to the Organon commercial laboratory). To minimize variability, we recommend utilizing a single laboratory that conducts routine proficiency testing for etonogestrel analysis within a study.
比较各实验室依托孕烯生物分析检测方法的性能特征。
我们开展了一项六实验室的盲法研究，其中包括五个学术实验室和一个签约商业实验室（参考实验室）。各实验室对六种已知依托孕烯浓度的制备血清和/或血浆样本以及60份使用含依托孕烯避孕方法的参与者的临床样本中的依托孕烯进行定量分析。根据监管指南，实验室准确性（偏差百分比）和精密度（变异系数；CV）定义为制备标称浓度的±15%。我们使用肯德尔tau - B检验和帕氏-巴布洛克回归分析比较实验室间和实验室内的一致性。
对于制备样本，六个实验室分析血清，三个实验室分析血浆。在包括参考实验室在内的四个实验室中，所有依托孕烯浓度下的所有结果准确性均在±15%以内。所有实验室均显示出高精度，仅出现一次CV>15%的情况。我们发现制备的血浆和血清中依托孕烯结果之间存在正相关（肯德尔tau - B检验，0.80 - 0.88）。对于临床样本，五个实验室分析血清，三个实验室分析血浆。与参考实验室相比，实验室间血清依托孕烯浓度呈正相关（肯德尔tau - B检验，0.76 - 0.95）。观察到比例偏差，即各实验室依托孕烯结果始终高于（斜率估计值0.78 - 0.95）或低于（斜率估计值1.05 - 1.10）参考实验室。在临床样本中，实验室内血浆和血清结果之间相关性良好（肯德尔tau - B检验，0.92 - 0.96）。
无论样本基质如何，实验室内一致性良好；然而，依托孕烯结果存在实验室间变异性。在比较不同研究中的依托孕烯药代动力学时，应考虑实验室结果之间的差异。
依托孕烯浓度在各实验室中高度精确，且血清和血浆之间具有可比性。各实验室结果有所不同（与欧加农商业实验室相比，高5 - 28%至低5 - 9%）。为尽量减少变异性，我们建议在一项研究中使用单个进行依托孕烯分析常规能力验证的实验室。
