(A) CRISPR-ABC signal in baseline blood samples of 34 adults with COVID-19 diagnosed by nasal or nasopharyngeal RT-qPCR and 125 archived blood samples collected before the COVID-19 pandemic. (B) SARS-CoV-2 RNA copy number in the 34 COVID-19 subjects. (C) Comparison of CRISPR-ABC signal values of blood samples from hospitalized (n = 25) and nonhospitalized (n = 9) patients with COVID-19 by a general linear model analysis adjusted for age. A and C are box plots with maximum, Q3, median, Q1, and minimum value of PL intensity of different groups. Dotted lines indicate the positive result threshold. Dashed lines in B indicate the linear range and LoQ and LoD of the CRISPR-ABC assay. All samples were analyzed in triplicate. ****P < 0.0001 by Mann-Whitney U test; ***P < 0.001 by general linear model analysis, adjusting for age and symptom duration differences between these groups.