Background: Antigen rapid diagnostic tests (RDT) for SARS-CoV-2 are fast, broadly available, and inexpensive. Despite this, reliable clinical performance data from large field studies is sparse. Methods: In a prospective performance evaluation study, RDT from three manufacturers (NADAL®, Panbio™, MEDsan®, conducted on different samples) were compared to quantitative reverse transcription polymerase chain reaction (RT-qPCR) in 5 068 oropharyngeal swabs for detection of SARS-CoV-2 in a hospital setting. Viral load was derived from standardised RT-qPCR Cycle threshold (C t ) values. The data collection period ranged from November 12, 2020 to February 28, 2021. Findings: The sensitivity of RDT compared to RT-qPCR was 42·57% (95% CI 33·38%–52·31%). The specificity was 99·68% (95% CI 99·48%–99·80%). Sensitivity declined with decreasing viral load from 100% in samples with a deduced viral load of ≥10 8 SARS-CoV-2 RNA copies per ml to 8·82% in samples with a viral load lower than 10 4 SARS-CoV-2 RNA copies per ml. No significant differences in sensitivity or specificity could be observed between samples with and without spike protein variant B.1.1.7. The NPV in the study cohort was 98·84%; the PPV in persons with typical COVID-19 symptoms was 97·37%, and 28·57% in persons without or with atypical symptoms. Interpretation: RDT are a reliable method to diagnose SARS-CoV-2 infection in persons with high viral load. RDT are a valuable addition to RT-qPCR testing, as they reliably detect infectious persons with high viral loads before RT-qPCR results are available.

Background Antigen rapid diagnostic tests (RDT) for SARS-CoV-2 are fast, broadly available, and inexpensive. Despite this, reliable clinical performance data is sparse. Methods In a prospective performance evaluation study, RDT from three manufacturers (NADAL, Panbio, MEDsan) were compared to quantitative reverse transcription polymerase chain reaction (RT-qPCR) in 5 068 oropharyngeal swabs for detection of SARS-CoV-2 in a hospital setting. Viral load was derived from standardized RT-qPCR Cycle threshold (Ct) values. The data collection period ranged from November 12, 2020 to February 28, 2021. Findings Overall, sensitivity of RDT compared to RT-qPCR was 42.57% (95% CI 33.38%-52.31%), and specificity 99.68% (95% CI 99.48%-99.80%). Sensitivity declined with decreasing viral load from 100% in samples with a deduced viral load of 10^8 SARS-CoV-2 RNA copies per ml to 8.82% in samples with a viral load lower than 104 SARS-CoV-2 RNA copies per ml. No significant differences in sensitivity or specificity could be observed between the three manufacturers, or between samples with and without spike protein variant B.1.1.7. The NPV in the study cohort was 98.84%; the PPV in persons with typical COVID-19 symptoms was 97.37%, and 28.57% in persons without or with atypical symptoms. Interpretation RDT are a reliable method to diagnose SARS-CoV-2 infection in persons with high viral load. RDT are a valuable addition to RT-qPCR testing, as they reliably detect infectious persons with high viral loads before RT-qPCR results are available. Funding German Federal Ministry for Education and Science (BMBF), Free State of Bavaria

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Background The role of cement-augmented screw fixation for calcaneal fracture treatment remains unclear. Therefore, this study was performed to biomechanically analyze screw osteosynthesis by reinforcement with either a calcium phosphate (CP)-based or polymethylmethacrylate (PMMA)-based injectable bone cement. Methods A calcaneal fracture (Sanders type IIA) including a central cancellous bone defect was generated in 27 synthetic bones, and the specimens were assigned to 3 groups. The first group was fixed with four screws (3.5 mm and 6.5 mm), the second group with screws and CP-based cement (Graftys® QuickSet; Graftys, Aix-en-Provence, France), and the third group with screws and PMMA-based cement (Traumacem™ V+; DePuy Synthes, Warsaw, IN, USA). Biomechanical testing was conducted to analyze peak-to-peak displacement, total displacement, and stiffness in following a standardized protocol. Results The peak-to-peak displacement under a 200-N load was not significantly different among the groups; however, peak-to-peak displacement under a 600- and 1000-N load as well as total displacement exhibited better stability in PMMA-augmented screw osteosynthesis compared to screw fixation without augmentation. The stiffness of the construct was increased by both CP- and PMMA-based cements. Conclusion Addition of an injectable bone cement to screw osteosynthesis is able to increase fixation strength in a biomechanical calcaneal fracture model with synthetic bones. In such cases, PMMA-based cements are more effective than CP-based cements because of their inherently higher compressive strength. However, whether this high strength is required in the clinical setting for early weight-bearing remains controversial, and the non-degradable properties of PMMA might cause difficulties during subsequent interventions in younger patients.