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Validation of diagnostic accuracy using digital slides in routine histopathology

László Fónyad1*, Tibor Krenács1, Péter Nagy1, Attila Zalatnai1, Judit Csomor1, Zoltán Sápi1, Judit Pápay1, Júlia Schönléber1, Csaba Diczházi1 and Béla Molnár2

Author Affiliations

1 First Department of Pathology and Experimental Cancer Research, Semmelweis University, Budapest, Hungary

2 Second Department of Internal Medicine, Semmelweis University, Budapest, Hungary

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Diagnostic Pathology 2012, 7:35  doi:10.1186/1746-1596-7-35

Published: 31 March 2012



Robust hardware and software tools have been developed in digital microscopy during the past years for pathologists. Reports have been advocated the reliability of digital slides in routine diagnostics. We have designed a retrospective, comparative study to evaluate the scanning properties and digital slide based diagnostic accuracy.


8 pathologists reevaluated 306 randomly selected cases from our archives. The slides were scanned with a 20× Plan-Apochromat objective, using a 3-chip Hitachi camera, resulting 0.465 μm/pixel resolution. Slide management was supported with dedicated Data Base and Viewer software tools. Pathologists used their office PCs for evaluation and reached the digital slides via intranet connection. The diagnostic coherency and uncertainty related to digital slides and scanning quality were analyzed.


Good to excellent image quality of slides was recorded in 96%. In half of the critical 61 digital slides, poor image quality was related to section folds or floatings. In 88.2% of the studied cases the digital diagnoses were in full agreement with the consensus. Out of the overall 36 incoherent cases, 7 (2.3%) were graded relevant without any recorded uncertainty by the pathologist. Excluding the non-field specific cases from each pathologist's record this ratio was 1.76% of all cases.


Our results revealed that: 1) digital slide based histopathological diagnoses can be highly coherent with those using optical microscopy; 2) the competency of pathologists is a factor more important than the quality of digital slide; 3) poor digital slide quality do not endanger patient safety as these errors are recognizable by the pathologist and further actions for correction could be taken.

Virtual slides

The virtual slide(s) for this article can be found here: webcite.

Retrospective study; Surgical pathology; Diagnostic error; Optical microscopy; Whole slide imaging