SARS-CoV-2 RNA Testing Using Different Assays-Impact on Testing Strategies in a Clinical Setting.

In order to assess SARS-CoV-2 real time quantitative polymerase chain reaction (RT-qPCR) results in a real-life setting, three independent laboratories in Graz (Austria) set up a continuous cross comparison schedule. The following test systems were used: The QIAGEN NeuMoDx SARS-CoV-2 Assay, the Allplex™ 2019-nCoV Assay (Seegene) on a MicroLab Nimbus (Hamilton) platform combined with RealStar SARS-CoV-2 RT-PCR Assay (Altona Diagnostics GmbH), and the cobas SARS-CoV-2 test on a fully automated cobas 6800 system (Roche). A total of 200 samples were analysed, 184 (92%) were found to be concordant with all testing platforms, 14 (7%) discordant. Two (1%) samples tested invalid on a single platform and were excluded from further analysis. Discordant results were distributed randomly across the assays. The Ct values from all assays correlated closely with each other. All discordant samples showed Ct values ≥ 26. SARS-CoV-2 RT-qPCR assays may show considerable variability, especially in samples with low viral RNA concentrations. Decision makers should thus balance the advantages and disadvantages of RT-qPCR for mass screening and adopt suitable strategies that ensure a rational management of positive samples with high Ct values.

[Systemic consequences and clinical aspects of SARS-CoV-2 infection]. / Systemische Auswirkungen und klinische Aspekte der SARS-CoV-2-Infektion.

BACKGROUND: COVID-19 is considered a systemic disease. A severe course with fatal outcome is possible and unpredictable. OBJECTIVES: Which organ systems are predominantly involved? Which diseases are predisposed for a fatal course? Which organ changes are found with lethal outcome? MATERIALS AND METHODS: Data from published autopsy studies (28 cases by our group) with respect to organ changes and possible cause of death. RESULTS: The most severe alterations are found in the lungs by diffuse alveolar damage as a symptom of an acute respiratory distress syndrome (ARDS), in part with fibrosis. Thrombosis of small- to mid-sized pulmonary arteries is associated with hemorrhagic lung infarction. Frequent complications are bacterial pneumonias and less frequently fungal pneumonias by aspergillus. Pulmonary thromboembolism is found in 20-30% of lethal courses, also in the absence of deep venous thrombosis. Intestinal involvement of COVID-19 can be associated with intestinal ischemia, caused by shock or local thrombosis. In most cases, the kidneys display acute tubular injury reflecting acute renal failure, depletion of lymphocytes in the lymph nodes and spleen, and hyperplastic adrenal glands. The liver frequently reveals steatosis, liver cell necrosis, portal inflammation, and proliferation of Kupffer cells. Important preexisting diseases in autopsy studies are arterial hypertension with hypertensive and ischemic cardiomyopathy and diabetes mellitus but large population-based studies reveal increased risk of mortality only for diabetes mellitus not for arterial hypertension. CONCLUSIONS: Alterations of the pulmonary circulation with pulmonary arterial thrombosis, infarction, and bacterial pneumonia are important and often lethal complications of COVID-19-associated ARDS. Findings from autopsy studies have influenced therapy and prophylaxis.

COVID-19 autopsies: Procedure, technical aspects and cause of fatal course. Experiences from a single-center.

Autopsies on COVID-19 have provided deep insights into a novel disease with unpredictable and potentially fatal outcome. A standardized autopsy procedure preferably with an in-situ technique and systematic tissue processing is important. Strict safety measures include personal protective equipment with a standardized protocol for dressing and undressing, usage of FFP-3 masks and minimization of aerosol production. The use of an airborne infection isolation (AIIR) room is preferred. Viral RNA analysis using swabs from throat, both lungs and other organs provides information on cross-organ viral dynamics. To correctly determine the full extent of pathological organ changes an adequate processing procedure is of the utmost importance. Systematic dissection and processing of the lungs revealed pulmonary infarction caused by thrombosis and thromboembolism and bacterial bronchopneumonia as the most frequent cause of death. Fungal pneumonia (aspergillus) was found in one case. The quality of the tissue was sufficient for histopathological and immunohistochemistry analyses in all cases. Viral RNA from throat or lung swabs was detectable post mortem in 89 % of the cases and could also be detected from paraffin-embedded tissue by real-time PCR. Complete COVID-19 autopsies including extensive histopathological studies and viral RNA analysis require approximately three times more human and technical resources and time compared to standard non-COVID autopsies. Autopsies on COVID-19 are feasible, present a manageable risk, while following a strict protocol, and provide novel insights into disease pathogenesis and the clinician with important feedback.