Background The accuracy of a new optical biosensor (OB) point-of-care device for the detection of severe infections is studied.Methods The OB emits different wavelengths and outputs information associated with heart rate, pulse oximetry, levels of nitric oxide and kidney function. At the derivation phase, recordings were done every two hours for three consecutive days after hospital admission in 142 patients at high-risk for sepsis by placing the OB on the forefinger. At the validation phase,

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... ngle recordings were done in 54 patients with symptoms of viral infection; 38 were diagnosed with COVID-19.Results At the derivation phase, the cutoff value of positive likelihood of 18 provided 100% specificity and 100% positive predictive value for the diagnosis of sepsis. These were 87.5% and 91.7% respectively at the validation phase. OB diagnosed severe COVID-19 with 83.3% sensitivity and 87.5% negative predictive value.Conclusions The studied OB seems valuable for the discrimination of infection severity.