ABSTRACT
From early 2020, a high demand for SARS-CoV-2 tests was driven by several testing indications, including asymptomatic cases, resulting in the massive roll-out of PCR assays to combat the pandemic. Considering the dynamic of viral shedding during the course of infection, the demand to report cycle threshold (Ct) values rapidly emerged. As Ct values can be affected by a number of factors, we considered that harmonization of semi-quantitative PCR results across laboratories would avoid potential divergent interpretations, particularly in the absence of clinical or serological information. A proposal to harmonize reporting of test results was drafted by the National Reference Centre (NRC) UZ/KU Leuven, distinguishing four categories of positivity based on RNA copies/mL. Pre-quantified control material was shipped to 124 laboratories with instructions to setup a standard curve to define thresholds per assay. For each assay, the mean Ct value and corresponding standard deviation was calculated per target gene, for the three concentrations (107, 105 and 103 copies/mL) that determine the classification. The results of 17 assays are summarized. This harmonization effort allowed to ensure that all Belgian laboratories would report positive PCR results in the same semi-quantitative manner to clinicians and to the national database which feeds contact tracing interventions.
Subject(s)
COVID-19 , SARS-CoV-2 , Belgium/epidemiology , COVID-19/diagnosis , COVID-19/epidemiology , Humans , Pandemics , Real-Time Polymerase Chain Reaction , SARS-CoV-2/geneticsABSTRACT
The 2014-2015 influenza season in Belgium was dominated by the circulation of 2 influenza A(H3N2) subgroups: 3C.2a and 3C.3b. Analysis of 166 nasopharyngeal aspirates, collected in patients with respiratory illness at the start of the epidemic season, showed a decreased sensitivity for the detection of influenza A(H3N2)/3C.2a using a commercially available multiplex assay. Gene sequencing of the matrix protein showed a point mutation (C163T) leading to a mismatch with the assay probes.
Subject(s)
Antigenic Variation/immunology , Influenza A virus/genetics , Influenza A virus/immunology , Influenza, Human/diagnosis , Influenza, Human/virology , Molecular Diagnostic Techniques/methods , Molecular Diagnostic Techniques/standards , Humans , Influenza A virus/classification , Influenza, Human/epidemiology , Influenza, Human/immunology , Mutation , Phylogeny , Polymerase Chain Reaction , RNA, Viral , Reagent Kits, Diagnostic , Reproducibility of Results , Seasons , Sensitivity and SpecificityABSTRACT
Cardiac tamponade is a life-threatening condition which must be quickly diagnosed and treated. This medical urgency can have several possible causes. We report the case of a 59-year-old patient presenting with a cardiac tamponade caused by extramedullary haematopoiesis due to myelofibrosis.
