Unità Operativa Complessa di Patologia Clinica, ASST Fatebenefratelli-Sacco, Milano, Italy.
Unità Operativa Laboratorio Analisi Chimico Cliniche e Microbiologiche, ASST Cremona, Cremona, Italy.
Clin Chem. 2021 Mar 1;67(3):543-553. doi: 10.1093/clinchem/hvaa268.
Previous studies have shown that the harmonization of prostate-specific antigen (PSA) assays remained limited even after the introduction of WHO International Standards. This information needs updating for current measuring systems (MS) and reevaluation according to established analytical performance specifications (APS) and the characteristics of antibodies used.
Total (tPSA) and free (fPSA) PSA were measured in 135 and 137 native serum samples, respectively, by Abbott Alinity i, Beckman Access Dxl, Roche Cobas e801, and Siemens Atellica IM MSs. Passing-Bablok regression and difference plots were used to compare results from each MS to the all-method median values. Agreement among methods was evaluated against APS for bias derived from biological variation of the 2 measurands.
The median interassay CV for tPSA MSs (11.5%; 25-75th percentiles, 9.2-13.4) fulfilled the minimum APS goal for intermethod bias (15.9%), while the interassay CV for fPSA did not [20.4% (25-75th percentiles, 18.4-22.7) vs goal 17.6%]. Considering the all-method median value of each sample as reference, all tPSA MSs exhibited a mean percentage bias within the minimum goal. On the other hand, Alinity (+21.3%) and Access (-24.2%) were out of the minimum bias goal for fPSA, the disagreement explained only in minimal part by the heterogeneity of employed antibodies.
The harmonization among tPSA MSs is acceptable only when minimum APS are applied and necessitates further improvement. The marked disagreement among fPSA MSs questions the use of fPSA as a second-level test for biopsy referral.
即使在引入世界卫生组织国际标准后，前列腺特异性抗原（PSA）检测的一致性仍然有限。 这一信息需要根据当前的测量系统（MS）进行更新，并根据既定的分析性能规格（APS）和使用的抗体特性进行重新评估。
分别使用 Abbott Alinity i、Beckman Access Dxl、Roche Cobas e801 和 Siemens Atellica IM MS 对 135 份和 137 份天然血清样本中的总（tPSA）和游离（fPSA）PSA 进行了测量。使用 Passing-Bablok 回归和差值图将每个 MS 的结果与所有方法的中位数进行比较。根据 2 个测定物的生物学变异衍生的偏倚，使用 APS 对方法间的一致性进行了评估。
tPSA MS 的批内 CV 中位数（11.5%；25-75 百分位数，9.2-13.4）满足偏倚的最小 APS 目标（15.9%），而 fPSA 的批内 CV 不满足[20.4%（25-75 百分位数，18.4-22.7）vs 目标 17.6%]。考虑到每个样本的所有方法中位数作为参考，所有 tPSA MS 的平均百分比偏差均在最小目标范围内。另一方面，Alinity（+21.3%）和 Access（-24.2%）的 fPSA 超出了最小偏差目标，其不一致性仅在一定程度上可以用所使用的抗体的异质性来解释。
仅当应用最小 APS 时，tPSA MS 之间的一致性才是可以接受的，并且需要进一步改进。fPSA MS 之间的明显差异质疑了将 fPSA 作为活检推荐的二级检测的使用。
