SARS-CoV-2 RNA screening in routine pathology specimens

Abstract

SummaryVirus detection methods are important to cope with the SARS-CoV-2 pandemics. Apart from the lung, SARS-CoV-2 was detected in multiple organs in severe cases. Less is known on organ tropism in patients developing mild or no symptoms, and some of such patients might be missed in symptom-indicated swab testing.Here we tested and validated several approaches and selected the most reliable RT-PCR protocol for the detection of SARS-CoV-2 RNA in patients’ routine diagnostic formalin-fixed and paraffin-embedded (FFPE) specimens available in pathology, to assess a) organ tropism in samples from COVID-19-positive patients, b) unrecognized cases in selected tissues from negative or not-tested patients during a pandemic peak, and c) retrospectively, pre-pandemic lung samples.We identified SARS-CoV-2 RNA in four samples from confirmed COVID-19 patients, in two gastric biopsies, one colon resection, and one pleural effusion specimen, while all other specimens, particularly from patients with mild COVID-19 disease course, were negative. In the pandemic peak cohort, we identified one previously unrecognized COVID-19 case in tonsillectomy samples. All pre-pandemic lung samples were negative.In conclusion, SARS-CoV-2 RNA detection in FFPE pathology specimens can potentially improve surveillance of COVID-19, allow retrospective studies, and advance our understanding of SARS-CoV-2 organ tropism and effects.

Complement activation induces excessive T cell cytotoxicity in severe COVID-19

“…Analysis of lung autopsy samples (cohort 3) RNA isolation and RT-PCR COVID-19 autopsy lung tissue samples were screened for the presence of morphological criteria consistent with diffuse alveolar damage and best tissue preservation. Three samples of each case were tested for SARS-CoV-2 RNA with RT-PCR as previously reported (von Stillfried et al, 2021;Wong et al, 2021).…”