An international, inter-laboratory ring trial confirms the feasibility of an open source, extraction-less "direct" RT-qPCR method for reliable detection of SARS-CoV-2 RNA in clinical samples (preprint)

RT-qPCR is used world-wide to test and trace the spread of SARS-CoV-2. Extraction-less or direct RT-PCR is an open-access qualitative method for SARS-CoV-2 detection from nasopharyngeal (NP) or oral pharyngeal (OP) samples with the potential to generate actionable data more quickly, at a lower cost, and with fewer experimental resources than full RT-qPCR. This study engaged ten global testing sites, including laboratories currently experiencing testing limitations due to reagent or equipment shortages, in an international inter-laboratory ring trial. Participating labs were provided a common protocol, common reagents, aliquots of identical pooled clinical samples and purified nucleic acids, and used their existing in-house equipment. We observed 100% concordance across labs in the correct identification of all positive and negative samples, with highly similar Ct values observed. The test also performed well when applied to locally collected patient NP samples, provided the viral transport media did not contain charcoal or guanidine, both of which appeared to potently inhibit the RT-PCR reaction. Our results suggest that open access, direct RT-PCR assays are a feasible option for more efficient COVID-19 testing as demanded by the continuing pandemic.

In-depth Analysis of Laboratory Parameters Reveals the Interplay Between Sex, Age and Systemic Inflammation in Individuals with COVID-19 (preprint)

Introduction: The progression and severity of the coronavirus disease 2019 (COVID-19), an infectious disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), varies significantly in the population. While the hallmarks of SARS-CoV-2 and severe COVID-19 within routine laboratory parameters are emerging, little is known about the impact of sex and age on these profiles. Methods: We performed multidimensional analysis of millions of records of laboratory parameters and diagnostic tests for 178,887 individuals, of which 33,266 tested positive for SARS-CoV-2. These included complete blood cell count, electrolytes, metabolites, arterial blood gases, enzymes, hormones, cancer biomarkers, and others. Results: COVID-19 induced more alterations in the laboratory parameters in males compared to females between 13 and 60 years old, in contrast to older individuals, where several parameters were altered by COVID-19 in both men and women. Biomarkers of inflammation, such as C-reactive protein (CRP) and ferritin, were increased especially in older men with COVID-19, whereas other markers such as abnormal liver function tests were common across several age groups, except for young women. Low peripheral blood basophils and eosinophils were also more common in the elderly with COVID-19. Both male and female COVID-19 patients admitted to the intensive care unit (ICU) displayed alterations in the coagulation system, and higher levels of neutrophils, CRP, lactate dehydrogenase (LDH), among others. Discussion: Our study uncovers the laboratory profile of a large cohort of COVID-19 patients that underly discrepancies influenced by aging and biological sex. These profiles directly link COVID-19 disease presentation to an intricate interplay between sex, age and the immune response.