Science Spotlight

Expedited SARS-CoV-2 testing saves lives of transplant patients

From the University of Washington and the Vaccine and Infectious Disease Division.
July 20, 2020 • By B Traxinger

The spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the resulting COVID-19 pandemic has compromised hospitals’ ability to perform life-saving solid organ transplants (SOT), due to risk of donor-to-recipient SARS-CoV-2 transmission and diversion of hospital resources to COVID-19 patients. For SOT procedures to continue efficiently during the pandemic, rapid SARS-CoV-2 testing of donors and recipients is necessary, as there is a short window of time in which a donated organ remains viable. However, SARS-CoV-2 testing ability in transplants settings has been limited due to supply chain shortages and lack of government approval.

The University of Washington Medical Center (UWMC), a large transplant hospital serving Washington and surrounding states, requires extensive and rapid SARS-CoV-2 testing of potential SOT donors and recipients. The UWMC clinical laboratory, which began testing for SARS-CoV-2 on March 2nd, 2020, sought to amplify their testing ability to support UWMC SOT procedures. They successfully designed and implemented an expedited, high-throughput testing system for donors and recipients, which they recently published in the American Journal of Transplantation.

This study, led by Dr. Joshua Lieberman of the University of Washington, aimed to expedite SARS-CoV-2 testing by asking a simple question. Dr. Lieberman explained: “How do we identify and prioritize moving high-consequence samples through a really busy clinical lab?” The team’s solution to this challenge was to ensure the SOT specimens were quickly identifiable, easily traced, and immediately processed. They executed these goals by attaching special printed flags to SOT specimens and implementing structured specimen handoffs to dedicated testing personnel, where upon arrival SOT samples were assigned highest testing priority.

During the March 31st to April 31st, 2020 study period, 43 samples at UWMC were screened for SARS-CoV-2 using the expedited testing structure, including 17 potential donors, 13 recipients, and 4 post-transplant patients requiring further procedures. In total, 32 organs were recovered from 14 organ donors and successfully transplanted in Washington state or in other regions.At UWMC, transplants were performed in 8 of 13 transplant candidates who were also screened with the expedited testing pathway. No donors or recipients tested positive, and using the expedited testing pipeline, only one test result was delayed, although no transplant procedure was delayed or prevented.

A, left) Turnaround time in hours (y-axis) by day result was reported (x-axis). Daily median turnaround time (TAT) for SARS-CoV-2 testing of inpatients performed at the UW Virology laboratory. Blue squares represent individual test TAT for potential organ donors and red squares represent individual TATs for organ recipients. Green exes indicate pre-transplant patients screened with a rapid test performed in the UW Microbiology laboratory starting on 3/31/2020. TATs for donors and recipients were significantly faster than daily medians (Wilcoxon signed-rank test, P = 6.6x10-9). B, right) Percent of total organ transplant waitlist inactivations due to COVID-19 precautions by region, starting 3/15/2020 (Week 1), corresponding to both the start of the expedited screening process and data collection for waitlist inactivations due to COVID-19. The proportion of inactivations due to COVID-19 concerns in the Northwest region (gold squares) was significantly different than national data (purple circles) and other regions at all time points, except where indicated (n.s., not significant; two-tailed Fisher’s Exact test). Data from https://unos.org/covid.
A, left) Turnaround time in hours (y-axis) by day result was reported (x-axis). Daily median turnaround time (TAT) for SARS-CoV-2 testing of inpatients performed at the UW Virology laboratory. Blue squares represent individual test TAT for potential organ donors and red squares represent individual TATs for organ recipients. Green exes indicate pre-transplant patients screened with a rapid test performed in the UW Microbiology laboratory starting on 3/31/2020. TATs for donors and recipients were significantly faster than daily medians (Wilcoxon signed-rank test, P = 6.6x10-9). B, right) Percent of total organ transplant waitlist inactivations due to COVID-19 precautions by region, starting 3/15/2020 (Week 1), corresponding to both the start of the expedited screening process and data collection for waitlist inactivations due to COVID-19. The proportion of inactivations due to COVID-19 concerns in the Northwest region (gold squares) was significantly different than national data (purple circles) and other regions at all time points, except where indicated (n.s., not significant; two-tailed Fisher’s Exact test). Data from https://unos.org/covid. Figure from publication.

“Although the system we put in place was simple, we were really surprised to see what looks like a big effect on the transplant waitlist,” Dr. Lieberman said. He explained that during the first week of the study, 152 hopeful transplant patients within the UWMC region were “inactivated,” or unable to receive an organ transplant, due to COVID-19 precautions. However, by the second week, no Northwest region patients were inactivated due to COVID-19, despite rapidly increasing COVID-19 cases in Washington during that time. “In contrast, the percent of waitlisted patients ‘inactivated’ due to COVID-19 in most other regions and around the country spiked in week two and stayed high,” Lieberman continued. Although the drop in COVID-19 inactivations can’t be proven to be a result of UWMC’s expedited SARS-CoV-2 screening alone, Dr. Lieberman is confident that their improved testing system “made a real contribution to sustaining organ recovery and organ transplant during this awful pandemic.”

While their new pipeline for screening SOT donors and recipients is now “running smoothly,” Lieberman explained that “there are a couple of key questions worth addressing as we go forward. First, what was the longitudinal impact of the system? This includes how many total organ donors and recipients did we screen, what were the positive rates for the virus, how was the waitlist affected, and how do these data compare to prior years? Second, now that antibody testing is available, what’s the role of that test? How many potential donors and recipients have SARS-CoV-2 antibodies now that the virus has smoldered in our region for months, and even accelerated in some places?” In addition to these outstanding technical questions, Dr. Lieberman discussed that future research is needed to address the biologic consequences of organ transplantation during a viral pandemic: “Big questions still remain about the immune response and clinical outcomes to SARS-CoV-2 infection in solid organ transplants.”

“We hope our experience will help other transplant centers and organ recovery organizations design systems that support their organ transplant programs,” Dr. Lieberman said.

UW/Fred Hutch Cancer Consortium member Keith Jerome contributed to this work.

Lieberman JA, Mays JA, Wells C, Cent A, Bell D, Bankson DD, Greninger AL, Jerome KR, Limaye AP. 2020. Expedited SARS-CoV-2 Screening of Donors and Recipients Supports Continued Solid Organ Transplant. Am J Transplant. doi: 10.1111/ajt.16081. Online ahead of print.

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