Telepathology in the Era of COVID-19
Safety Assessment
Aleksandra Zuraw, DVM, PhD

Telepathology in the Era of COVID-19

The pandemic has put a whole different spin on how we analyze slides remotely

Like many other professionals, pathologists have been instructed to work from home during the coronavirus pandemic. Even those of us who were hesitant for one reason or another are being pushed towards some form of telepathology.

Before the pandemic one would consider using a telepathology system:

  • in remote areas, with no access to pathologists, such as northern Norway and Canada as well as many African countries
  • for immediate frozen section evaluation when no pathologist was on site
  • for educational purposes
  • for proficiency testing in laboratories
  • for second opinion consultations and tumor boards
  • for peer review of toxicopathological studies
  • and far less frequently (especially in the US) for primary clinical diagnosis

Now, with the necessity of remote work for the past three months, the adoption of this technology has grown exponentially.

What is telepathology?

The broadest definition of telepathology is “the practice of pathology at a distance, often with use of telecommunication technologies”. The modern telecommunication technologies, such as digital whole slide image (WSI) transfer via the internet are incorporated in most of the current digital pathology applications. Less mainstream methods, such as a microscope camera over Skype or snapping pictures with your cell phone to consult with colleagues and tech students via WhatsApp fall also into this category. These tools are used frequently all over the world. Nowadays with easy access to the internet and digital cameras we really can get creative, but how was telepathology conducted in the “old” days? And what exactly triggered the development of this technology?

The origins of telepathology – how did it all start?

As simple and unspectacular as it sounds, telepathology was born out of the need for quick remote consultation, but it was not a simple consultation between colleagues.

It is not a secret that pathologists often disagree regarding diagnoses. Pathology is not an exact science and the diagnosed diseases often do not have sharp boundaries either. Therefore, there are tumor boards, pathology working groups and other pathology committees aiming to help reach a consensus in difficult cases. However, as common as those disagreements are, it is always a problem when patients’ lives are affected by them.

This was the case during the bladder cancer clinical trials of the National Bladder Cancer Project ( run in the 1980’s. The discrepancies between the institutions recruiting patients for the clinical trials and the central reviewing laboratory of the project were so significant, that they resulted in changing the patients’ treatment regimen. It would not have been a problem if this happened before the treatment started, but because there was a big lag between the original diagnosis and the central review, the patients were already being treated according to the often incorrect original diagnoses and had to change medications in the middle of treatment. This obviously made the clinical trial data impossible to interpret. It caused a real crisis in the National Bladder Cancer Project, and it sparked the development of the first telepathology system. The review of the diagnosis absolutely had to happen in real time!

Dr. Ronald Weinstein was the director of the National Bladder Cancer Project central laboratory and was involved in reviewing the discrepant diagnoses. As an innovator and a serial entrepreneur, he was tasked with developing a system that would enable centralized review of the diagnosis before the patients were enrolled in the trial. In 1985 together with his sister he co-founded Corabi International Telemetrics, Inc, and in 1986 brought to life the first analogue dynamic-robotic microscopy system for remote diagnosis. He also introduced the term “telepathology” to the pathology field.

The microscopy system worked by sending images from a microscope located in one place to a TV monitor located in a different place via a bi-directional microwave telecommunications system. This enabled the remote observer to steer the microscope stage in the original location.

Fast-forward 34 years and we all can have telepathology on our smartphones in our pockets…

Telepathology and toxicologic pathology

After whole slide scanners became commercially available, the extreme ease of pathology slide digitization fostered quick adoption of telepathology in education and other non- regulated areas such as veterinary diagnostics. However, it took significantly longer for it to enter the regulated environment. In human pathology until recently, the CLIA regulations did not permit for remote sign off from non-CLIA certified locations such as pathologists’ homes.

The preclinical area of toxicologic pathology operates within the Good Laboratory Practice (GLP) regulatory framework. It does not preclude veterinary pathologists from taking their microscopes and slides to their home offices and continuing their work on primary review of their studies. This is exactly what happened during the current pandemic.

However, another part of the toxicopathologic workflow – the peer review – where the slides, already reviewed and diagnosed by the study pathologist, need to be reviewed again by another pathologist posed a bigger challenge. In these situations, the peer review pathologist must travel to the primary review location to review the slides and discuss the findings with the primary review pathologist. Obviously this was not possible this year once international travel bans were implemented across the globe. One solution to this problem was to ship the slides to the peer review pathologist, but this created increased work for the laboratory personnel, who would have had to  pack and unpack thousands of slides (yes, these are the numbers in a toxicopathologic study…) in addition to other shipment related activities, costs, and time.

To get around this roadblock, pathologists started using digitized slides and digital pathology systems to accelerate the process. We are happy to report that Charles River Laboratories and several partners rapidly moved in that direction. The slides were scanned and transferred to the peer review pathologist digitally and the peer reviews took place as scheduled, causing only minimal changes in the laboratory workflow. As more and more partners are interested in “tele-peer review” we are scaling our capacities and working with them to increase our efficiency.


The term telepathology, referring to practicing pathology at a distance, was first used in the 1986. Since then a lot has happened in this discipline including going from analogue to digital systems and telepathology’s “merger” with the discipline of digital pathology. Due to the COVID19 pandemic, the CMS and FDA agencies are loosening up regulations and allowing pathologists to use digital pathology hardware and software that has not been approved yet and are allowed to sign off remotely, which, although only temporary, is a huge regulatory leap. Toxicologic pathologists started using digital pathology platforms for peer review and validation efforts and have planned to expand the application to primary review as well.

Currently telepathology is undergoing accelerated adoption, acceptance and an incredible gain of momentum in all preclinical and clinical areas of pathology. Even though these advances are forced by the COVID-19 pandemic, they are very likely to become permanently embedded in the pathologists’ workflow benefiting them beyond the current crisis.  

To learn more about this option check out Charles River’s digital pathology services.