Editors: Olga Pozdnyakova, MD, PhD, Geoffrey Wool, MD, PhD, David Bernard, MD, PhD & Raul S. Gonzalez, MD
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Q. Is telepathology used much in the United States for histology interpretation and diagnosis? For example, is it used to interpret digitally transmitted histology slides when working from home?
A. October 2025— In the CAP’s 2024 Practice Characteristics Survey, 24 percent of 964 U.S.-based board-certified pathologists reported that they perform remote sign-out, and 12 percent said they planned to do so within 12 months. Remote sign-out was most prevalent in independent laboratories, with 67 percent of independent lab respondents indicating that they perform it in some form. (The survey report did not break down remote sign-out by type.)
The use of telepathology in the United States has grown significantly since the onset of COVID. At the start of the pandemic, the Centers for Medicare and Medicaid Services waived the requirement for remote locations to have separate CLIA licenses provided the primary site had a CLIA certificate, and the FDA issued guidance on a policy to help expand the availability of remote digital pathology devices in an effort to facilitate access to diagnostic services.
As remote reading became more feasible and necessary, laboratories nationwide invested in digital capabilities. In doing so, they generated a wealth of evidence supporting the operational and financial benefits of telepathology, as well as its positive impact on job satisfaction. Therefore, many of the pathologists who began using the technology during COVID continued to use it after the FDA’s emergency use authorization ended, thereby providing laboratories that had yet to embrace digitization with a blueprint for success.
Now, with the pandemic behind us but the shortage of pathologists lingering, laboratories are continuing to adopt digital pathology, in part for telepathology. Spectrum Healthcare Partners, Maine’s largest statewide physician-owned multispecialty practice, is a good example. It provides pathology services to many hospitals in Maine and eastern New Hampshire and went digital to tap into a broader talent pool and reduce the need for specialist pathologists to drive two to three hours to various physical laboratories to provide the coverage needed.
Tumor boards and consults are also great use cases for telepathology.
College of American Pathologists. 2024 Practice Characteristics Survey Report. October 2024.
Nathan Buchbinder
Chief Strategy Officer
Proscia
Philadelphia, Pa.
The following question and answer was first published in July 2022. We periodically republish answers to questions that remain important and current. At the time of initial publication, Dr. Smock was vice chair of the CAP Hemostasis and Thrombosis Committee.
Q. When a patient has a hematocrit level of ≥ 55 percent and a normal PT and APTT, do you still correct sodium citrate and ask for a redraw? Is it crucial to ask for a redraw when the emergency department orders a stat PT and APTT?
A. CLSI document H21-A5 addresses the need to adjust citrate concentration for patients with high hematocrits since hematocrits above 55 percent lead to a relative excess of citrate in blue-top tubes that may cause prolonged clotting times. I am not aware of guidance that addresses the need to redraw a sample for which citrate has been adjusted if the prothrombin time (PT) and activated partial thromboplastin time (APTT) are normal, which means laboratory directors can use their discretion in managing such situations.
Our laboratory would allow the normal results to be reported since the high hematocrit may lead to erroneous prolonged clotting times but would not be expected to cause erroneous normal clotting times.
The decision whether to redraw should take into consideration which tests are ordered since expected effects and potential clinical significance may be different for different assays. Therefore, the laboratory’s written procedure outlining the handling of polycythemic specimens should address the potential for erroneous results for calcium-dependent clotting tests, including routine (e.g. PT, PTT) and specialized (e.g. clottable protein C, protein S) coagulation testing.
Clinical and Laboratory Standards Institute. H21-A5: Collection, Transport, and Processing of Blood Specimens for Testing Plasma-Based Coagulation Assays and Molecular Hemostasis Assays; Approved Guideline, 5th ed.; 2008.
College of American Pathologists. HEM.36900 Elevated hematocrits—coagulation. In: Hematology and coagulation checklist. Sept. 22, 2021.
Marlar RA, Potts RM, Marlar AA. Effect on routine and special coagulation testing values of citrate anticoagulant adjustment in patients with high hematocrit values. Am J Clin Pathol. 2006;126(3):400–405.
Kristi J. Smock, MD
Professor of Pathology
University of Utah School of Medicine
Hematopathology Medical Director
Hemostasis/Thrombosis Laboratory
ARUP Laboratories
Salt Lake City, Utah
Chair, CAP Hemostasis and Thrombosis Committee