Van Hoovels Lieve, Bossuyt Xavier, Manfredi Mariangela, Grossi Valentina, Benucci Maurizio, Van Den Bremt Stefanie, De Baere Heidi, Franceschi Daria, Tosi Emiliano, Meoni Marco, Bizzaro Nicola, Infantino Maria
Department of Laboratory Medicine, OLV Hospital, Aalst, Belgium.
Department of Microbiology and Immunology, KU Leuven, Leuven, Belgium.
Clin Chem Lab Med. 2021 Feb 17;59(7):1247-1255. doi: 10.1515/cclm-2020-1669. Print 2021 Jun 25.
Currently available computer-aided diagnosis (CAD) systems for the detection of anti-nuclear antibodies (ANA) by indirect immunofluorescence (IIF) assay enable a standardized measurement of system-specific fluorescent intensity (FI) measures. We aimed to evaluate an internal quality control (iQC) program that controls the total ANA IIF process in routine practice.
In addition to the kit iQC materials, supplemental quality indicators were integrated in a total quality assurance (QA) program: patient-derived iQC's samples (negative, 1/160 fine speckled and 1/160 homogeneous), median sample FI per run and percentage of ANA IIF positive samples per run. Analytical rejection criteria were based on the imprecision of the positivity index (PI) measure of the Zenit PRO system (Menarini). Clinical rejection criteria were based on changes in FI that correspond to a change in ANA IIF titer of ≥2. To evaluate the QA program, different artificial errors were introduced during the ANA IIF process. After every run, quality indicators were evaluated and compared to the pre-set target values.
Rescanning the ANA IIF slides five times, using an old conjugate and a needle obstruction resulted in analytically and even clinically relevant errors in ANA IIF results. All errors were correctly detected by the different defined quality indicators. Traditional Westgard rules, including analytically (and clinically) defined rejection limits were useful in monitoring quality indicators.
The integration of a total process iQC program in CAD systems, based on the specific FI measurands and performance criteria of the system, adds value to QA.
目前可用的通过间接免疫荧光（IIF）检测抗核抗体（ANA）的计算机辅助诊断（CAD）系统能够对系统特异性荧光强度（FI）测量值进行标准化测量。我们旨在评估一项在常规实践中控制整个ANA IIF检测过程的内部质量控制（iQC）程序。
除试剂盒iQC材料外，补充质量指标被整合到一个全面质量保证（QA）程序中：患者来源的iQC样本（阴性、1/160细颗粒型和1/160均质型）、每次运行的样本FI中位数以及每次运行的ANA IIF阳性样本百分比。分析性拒收标准基于Zenit PRO系统（美纳里尼公司）阳性指数（PI）测量的不精密度。临床拒收标准基于与ANA IIF滴度变化≥2相对应的FI变化。为评估QA程序，在ANA IIF检测过程中引入了不同的人为误差。每次运行后，对质量指标进行评估并与预设目标值进行比较。
对ANA IIF玻片进行五次重新扫描、使用旧的结合物和针头堵塞导致ANA IIF结果出现分析性甚至临床相关误差。所有误差均被不同定义的质量指标正确检测到。包括分析性（和临床）定义的拒收限值在内的传统韦斯特加德规则在监测质量指标方面很有用。
基于系统特定的FI测量值和性能标准，在CAD系统中整合整个过程的iQC程序可为QA增添价值。
