Whole slide imaging (WSI) has advanced to a point where it could replace the glass slide as primary Means of pathology evaluation. In general, a virtual slide is made using a computer System that scan the entire slide-base Specimen at high Magnification and stores all image data in electronic file system. Although, the FDA recently confirmed the non inferiority of the WSI Philips IntelliSite Pathology Solution (PIPS) compared to the light microscope, they outlined a list of specificities and required in depth bench testing. It is reasonable to assume that regulatory guidelines for WSI Within a non-Clinical GLP environment should follow the bench and system tests from a clinical use. Therefore, Within a GLP environment, all hardware Used in the digital pathology workflow will need to be validated and its use should be controlled by standard Operating Procedures (SOP).

Pathology Raw Data has been clearly defined in both FDA’s 1987 Final Rule and the OECD’s 2014 Advisory Document of the working group on Good laboratory Practices as only the signed and dated final report of the pathologists. according to the GLP regulations, 21 CFR Part 58, 58.3 (k), raw data may also include worksheets, records, notes or exact copies therfo that are the result of original observations and activities and are necessary for the reconstruction and evaluation of the final report. Although the notes or images captured by a pathologist during histopathological examination of slides are indeed the results of original observations, these notes or images are not necessary for the construction and evaluation of the final report. Further, because section 58.190(a) requires histopathological blocks, tissues and slides to be retained as specimen, the final report can be reconstructed by verification of the pathology Finding's.

it’s noteworthy to mention that most of the time pathologists who are working With WSI in a GLP-regulated Environment still keep the original glass specimen as a reference. if WSI on the level of primary diagnosis remain more and more convenient, the digital image is a high-resolution copy of a tissue section on a glass slide, but it is not an exact replica in every way and same tissue samples may look differently when image/scanned with different instruments, viewed on different displays or even assessed with different sofware viewers. the digital image remains the specimen as it is derived from the test system. It happens also that the pathologist may need additional sources of data (eg. clinical pathology data) for its final diagnosis. Consequently, the signed and dated pathology report remain the raw data respecting the histopathological evaluation if tissue specimens according to the 1987 preable. when images and results are presented in the Pathology report, they may need to be considered as “part of the raw data”. as the original glass slides are archived as per SOP, there Would be no requirement to archive the digital scans. If the scanned image is Used for image analysis for the purpose of data generation (eg.morphometry), then the would become image raw data that must be authenticated and archived.

Dr. Neyens Elizabeth

DABT, Pathologist Certified in Digital Pathology