Cheung Carol C, Swanson Paul E, Nielsen Søren, Vyberg Mogens, Torlakovic Emina E
Department of Pathology, Laboratory Medicine Program, University Health Network.
Department of Laboratory Medicine and Pathobiology, Faculty of Medicine, University of Toronto, Toronto, Ontario.
Appl Immunohistochem Mol Morphol. 2018 May/Jun;26(5):299-304. doi: 10.1097/PAI.0000000000000656.
The occurrence of uneven staining (UES) in automated immunohistochemistry (IHC) has been experienced by clinical laboratories and has the potential to confound readout, interpretation, and reporting of IHC assays despite the presence optimally stained on-slide controls. However, there are no studies of this phenomenon in regard to the type, frequency, and association with different automated IHC platforms. We studied the occurrence of UES in automated IHC assays with real world examples from clinical practice and by using a laboratory developed methodology to monitor baseline and periodic performance of automated IHC instruments.
Sections of formalin-fixed, paraffin-embedded normal liver tissue were mounted on 180 glass slides and stained for HepPar1 on 6 automated IHC instruments (4 different models from 3 different manufacturers). Macroscopic and microscopic defects of staining were recorded.
Only 8% of slides showed completely uniform staining. UES, including areas of both increased and decreased staining, occurred with all instruments. Decreased staining was often zonal, involving large regions of the slide. Decreased staining mostly localized in an instrument-dependent manner. Increased staining tended to occur in small foci with a random distribution.
The common occurrence of UES (particularly decreased staining) has important implications for the reliable read-out of IHC assays on biopsy samples. Baseline and periodic quality assurance testing for UES is recommended for all automated IHC instruments.
临床实验室在自动免疫组织化学（IHC）中遇到过不均匀染色（UES）的情况，尽管载玻片上有最佳染色的对照，但仍有可能混淆IHC检测的读数、解释和报告。然而，关于这种现象的类型、频率以及与不同自动IHC平台的关联，尚无相关研究。我们通过临床实践中的实际例子，并使用实验室开发的方法来监测自动IHC仪器的基线和定期性能，研究了自动IHC检测中UES的发生情况。
将福尔马林固定、石蜡包埋的正常肝组织切片装载到180张载玻片上，并在6台自动IHC仪器（来自3个不同制造商的4种不同型号）上进行HepPar1染色。记录染色的宏观和微观缺陷。
只有8%的载玻片显示完全均匀的染色。所有仪器均出现了UES，包括染色增加和减少的区域。染色减少通常呈带状，涉及载玻片的大片区域。染色减少大多以仪器依赖的方式定位。染色增加倾向于以随机分布的小病灶形式出现。
UES的普遍存在（尤其是染色减少）对活检样本IHC检测的可靠读数具有重要意义。建议对所有自动IHC仪器进行UES的基线和定期质量保证检测。
