Diagnosing COVID-19; towards a feasible COVID-19 rule-out protocol.

INTRODUCTION: We present the results of the COVID-19 rule-out protocol at Ghent University Hospital, a step-wise testing approach which included repeat NFS SARS-CoV-2 rRT-PCR, respiratory multiplex RT-PCR, low-dose chest CT and bronchoscopy with BAL to confirm or rule-out SARS-CoV-2 infection in patients admitted with symptoms suggestive of COVID-19. RESULTS: Between 19 March 2020 and 30 April 2020, 455 non-critically ill patients with symptoms suspect for COVID-19 were admitted. The initial NFS for SARS-CoV-2 rRT-PCR yielded 66.9%, the second NFS 25.4% and bronchoscopy with BAL 5.9% of total COVID-19 diagnoses. In the BAL fluid, other respiratory pathogens were detected in 65% (13/20) of the COVID-19 negative patients and only in 1/7 COVID-19 positive patients. Retrospective antibody testing at the time around BAL sampling showed a positive IgA or IgG in 42.9 % of the COVID-19 positive and 10.5% of the COVID-19 negative group. Follow-up serology showed 100% COVID-19 positivity in the COVID-19 positive group and 100% IgG negativity in the COVID-19 negative group. CONCLUSION: In our experience, bronchoscopy with BAL can have an added value to rule-in or rule-out COVID-19 in patients with clinical and radiographical high-likelihood of COVID-19 and repeated negative NFS testing. Furthermore, culture and respiratory multiplex PCR on BAL fluid can aid to identify alternative microbial etiological agents in this group. Retrospective analysis of antibody development in this selected group of patients suggests that the implementation of serological assays in the routine testing protocol will decrease the need for invasive procedures like bronchoscopy.

The epidemic of cardio-vascular disease in renal failure: where does it come from, where do we go?

Cardio-vascular disease and death are among the most important medical and socio-economic challenges of the 21st century. Renal failure, a major medical problem per se, gives rise to an accelerated and strongly magnified model of atherogenesis and vascular damage. Already with a minor decrease in renal function, coronary and vascular risk are increased and play a role next to classical risk factors such as male gender, diabetes mellitus, hypercholesterolemia or smoking. The impact of renal failure on cardio-vascular risk remains present even after correction for these traditional risk factors. This suggests that factors specifically related to renal failure play a role. Atheromatosis is currently considered as an inflammatory disorder. Renal failure gives rise to enhanced inflammatory parameters. However, the atherogenic factors related to this inflammation remain largely unknown. Hence, the condition of renal failure may be helpful to answer this question. According to recent data from the USA, close to 5% of the general population (11% of those older than 65 without diabetes or hypertension) has a renal function which is decreased by at least 50%, but other analyses come up with even higher figures. Better identification of the factors at play in this population, optimized secondary preventive actions similar to those applied in diabetics, and timely screening and therapy will be helpful to improve quality of life and reduce socio-economic burden in this population.