Department of Obstetrics, University of Leipzig, Liebigstr. 20a, 04103, Leipzig, Germany.
Roche Diagnostics International Ltd, Rotkreuz, Switzerland.
Clin Chem Lab Med. 2019 Aug 27;57(9):1339-1348. doi: 10.1515/cclm-2018-1228.
Background For pregnant women with suspected preeclampsia, the soluble fms-like tyrosine-kinase 1 (sFlt-1)/placental growth factor (PlGF) ratio is a biomarker to aid diagnosis. We performed method comparisons between Elecsys® and Kryptor sFlt-1 and PlGF immunoassays and assessed the diagnostic performance for preeclampsia. Methods Serum samples from a case-control study involving 113 pregnant women with preeclampsia/elevated liver enzymes and low platelet count (HELLP) and 270 controls were analyzed. sFlt-1 and PlGF were measured using Roche Elecsys® and BRAHMS Kryptor sFlt-1/PlGF immunoassays. The sFlt-1/PlGF ratios were calculated, and Passing-Bablok regression/Bland-Altman plots were performed. Gestation-specific cut-offs, ≤33 and ≥85/≥110, were assessed. Results Mean (±2 standard deviation [SD]) differences between the Elecsys® and Kryptor values were: sFlt-1, 173.13 pg/mL (6237.66, -5891.40); PlGF, -102.71 pg/mL (186.06, -391.48); and sFlt-1/PlGF, 151.74 (1085.11, -781.63). The Elecsys® and Kryptor immunoassays showed high correlation: Pearson's correlation coefficients were 0.913 (sFlt-1) and 0.945 (PlGF). Slopes were 1.06 (sFlt-1) and 0.79 (PlGF), resulting in ~20% lower values for Kryptor PlGF. Sensitivities and specificities using the sFlt-1/PlGF ≥85 cut-off for early-onset preeclampsia (20 + 0 to 33 + 6 weeks) were 88.1%/100.0% (Elecsys®) and 90.5%/96.2% (Kryptor), respectively, and using the ≥110 cut-off for late-onset preeclampsia (≥34 + 0 weeks) were 51.3%/96.5% (Elecsys®) and 78.9%/90.1% (Kryptor), respectively. Using Elecsys® and Kryptor sFlt-1/PlGF, 0% and 3.8% of women, respectively, were falsely ruled-in for early-onset, and 3.5% and 9.9%, respectively, for late-onset preeclampsia. Conclusions Despite high correlation between the Elecsys® and Kryptor immunoassays, we observed significant differences between sFlt-1/PlGF and PlGF results. Therefore, sFlt-1/PlGF cut-offs validated for Elecsys® immunoassays are not transferable to Kryptor immunoassays.
对于疑似子痫前期的孕妇，可溶性 fms 样酪氨酸激酶 1（sFlt-1）/胎盘生长因子（PlGF）比值是一种辅助诊断的生物标志物。我们比较了 Elecsys®和 Kryptor sFlt-1 和 PlGF 免疫分析之间的方法，并评估了其用于子痫前期的诊断性能。
分析了一项涉及 113 例子痫前期/肝酶升高和血小板计数低（HELLP）孕妇和 270 例对照的病例对照研究的血清样本。使用罗氏 Elecsys®和 BRAHMS Kryptor sFlt-1/PlGF 免疫分析法测量 sFlt-1 和 PlGF。计算 sFlt-1/PlGF 比值，并进行 Passing-Bablok 回归/ Bland-Altman 图分析。评估了特定于妊娠的截断值，≤33 和≥85/≥110。
Elecsys®和 Kryptor 值之间的平均（±2 个标准差[SD]）差异为：sFlt-1，173.13 pg/mL（6237.66，-5891.40）；PlGF，-102.71 pg/mL（186.06，-391.48）；和 sFlt-1/PlGF，151.74（1085.11，-781.63）。Elecsys®和 Kryptor 免疫分析显示出高度相关性：Pearson 相关系数分别为 0.913（sFlt-1）和 0.945（PlGF）。斜率分别为 1.06（sFlt-1）和 0.79（PlGF），导致 Kryptor PlGF 约低 20%。使用 sFlt-1/PlGF≥85 的截断值，用于早期子痫前期（20+0 至 33+6 周）的 Elecsys®的灵敏度和特异性分别为 88.1%/100.0%（Elecsys®）和 90.5%/96.2%（Kryptor），而使用晚期子痫前期（≥34+0 周）的≥110 截断值的灵敏度和特异性分别为 51.3%/96.5%（Elecsys®）和 78.9%/90.1%（Kryptor）。使用 Elecsys®和 Kryptor sFlt-1/PlGF，分别有 0%和 3.8%的女性被错误地归类为早期发病，分别有 3.5%和 9.9%的女性被错误地归类为晚期发病。
尽管 Elecsys®和 Kryptor 免疫分析之间具有高度相关性，但我们观察到 sFlt-1/PlGF 和 PlGF 结果之间存在显著差异。因此，针对 Elecsys®免疫分析验证的 sFlt-1/PlGF 截断值不能转移到 Kryptor 免疫分析。
