Digital immunohistochemistry implementation, training and validation: experience and technical notes from a large clinical laboratory

Aims: To consider the value proposition of digitisation of clinical immunohistochemistry services, and to develop an approach to digital immunohistochemistry implementation and validation in a large clinical laboratory.

Methods: A methodology for slide scanning in the laboratory was developed, in addition to a novel validation exercise, to allow pathologists to identify the strengths and weaknesses of digital immunohistochemistry reporting, and train in digital immunohistochemistry slide assessment.

Results: A total of 1480 digital immunohistochemistry slides were assessed by 24 consultant pathologists, with complete clinical concordance between the digital and the glass slide assessment observed. Certain stains were identified as being difficult/time consuming to assess using ×20 digital slides. These stains were rescanned at ×40, which improved the confidence of the pathologists to make a digital assessment. Full digitisation of immunohistochemistry slides was achieved, introducing six new steps into the pre-existing laboratory workflow.

Conclusions: While initially encountering challenges in terms of workflow, our experience showed that a well-designed, adequately resourced and well-managed scanning process can minimise the delay in slides being made available for review. Our approach to validation highlighted the need for careful assessment of a digital pathology system and scanning protocols before pathologists are expected to transfer from the light microscope to the digital microscope for routine immunohistochemistry assessment.