Evaluation of four laboratory-based high-throughput SARS-CoV-2 automated antigen tests compared to RT-PCR on nasal and oropharyngeal samples.

BACKGROUND: The demand for RT-PCR testing has been unprecedented during the SARS-CoV-2 pandemic. Fully automated antigen tests (AAT) are less cumbersome than RT-PCR, but data on performance compared to RT-PCR are scarce. METHODS: The study consists of two parts. A retrospective analytical part, comparing the performance of four different AAT on 100 negative and 204 RT-PCR positive deep oropharyngeal samples divided into four groups based on RT-PCR cycle of quantification levels. In the prospective clinical part, 206 individuals positive for and 199 individuals negative for SARS-CoV-2 were sampled from either the anterior nasal cavity (mid-turbinate) or by deep oropharyngeal swabs or both. The performance of AATs was compared to RT-PCR. RESULTS: The overall analytical sensitivity of the AATs differed significantly from 42% (95% CI 35-49) to 60% (95% CI 53-67) with 100% analytical specificity. Clinical sensitivity of the AATs differed significantly from 26% (95% CI 20-32) to 88% (95% CI 84-93) with significant higher sensitivity for mid-turbinate nasal swabs compared to deep oropharyngeal swabs. Clinical specificity varied from 97% to 100%. CONCLUSION: All AATs were highly specific for detection of SARS-CoV-2. Three of the four AATs were significantly more sensitive than the fourth AAT both in terms of analytical and clinical sensitivity. Anatomical test location significantly influenced the clinical sensitivity of AATs.

Lipoprotein(a) during COVID-19 hospitalization: Thrombosis, inflammation, and mortality.

BACKGROUND AND AIMS: High levels of lipoprotein(a) could worsen the outcome of COVID-19 due to prothrombotic and proinflammatory properties of lipoprotein(a). We tested the hypotheses that during COVID-19 hospitalization i) increased thrombotic activity and inflammation are associated with lipoprotein(a) levels, and ii) lipoprotein(a) levels are associated with rate of hospital death and discharge. METHODS: We studied 211 patients admitted to Copenhagen University Hospital in 2020 with COVID-19, that is, prior to any vaccination. Thrombotic activity was marked by elevated D-dimer while inflammation was marked by elevated interleukin-6, C-reactive protein, and procalcitonin. Patients were followed until death (N = 36) or discharge (N = 175). RESULTS: A 2-fold higher D-dimer was associated with 14% (95%CI: 8.1-20%) higher lipoprotein(a). Conversely, 2-fold higher interleukin-6, C-reactive protein, and procalcitonin were associated with respectively 4.3% (0.62-7.8%), 5.7% (0.15-5.2%), and 8.7% (5.2-12%) lower lipoprotein(a). For hospital death, the multivariable adjusted hazard ratio per 2-fold higher lipoprotein(a) was 1.26 (95%CI:0.91-1.73). Corresponding hazard ratios per 2-fold higher biomarker were 0.93 (0.75-1.16) for D-dimer, 1.42 (1.17-1.73) for interleukin-6, 1.44 (0.95-2.17) for C-reactive protein, and 1.44 (1.20-1.73) for procalcitonin. For hospital discharge, the multivariable adjusted hazard ratio per 2-fold higher lipoprotein(a) was 0.91 (95%CI:0.79-1.06). Corresponding hazard ratios per 2-fold higher biomarker were 0.86 (0.75-0.98) for D-dimer, 0.84 (0.76-0.92) for interleukin-6, 0.80 (0.71-0.90) for C-reactive protein, and 0.76 (0.67-0.88) for procalcitonin. CONCLUSIONS: In COVID-19 patients, thrombotic activity marked by elevated D-dimer was associated with higher lipoprotein(a) while elevated inflammatory biomarkers of interleukin-6, C-reactive protein, and procalcitonin were associated with lower lipoprotein(a); however, elevated lipoprotein(a) was not associated with rate of hospital death or discharge.