ABSTRACT
Introduction: SARS-CoV-2 has been found in the heart of COVID-19 patients. It is unclear how the virus passes from the upper respiratory tract to the myocardium. Hypothesis: SARS-CoV-2 is present in the blood of COVID-19 infected patients. Methods: We targeted two viropotins, Orf3a and E, in SARS-CoV-2. Orf3a and E form non-voltagegated ion channels. A combined fluorescence potassium ion assay with three channel modulators (4-aminopyridine, emodin-Orf3a channel blocker, gliclazide-E channel blocker) was developed to detect SARS-CoV-2 Orf3a/E channel activity. In blood samples, we subtracted the fluorescence signals in the absence and presence of emodin/gliclazide to detect Orf3a and E channel activity. Results: In lentivirus spiked samples, we detected significant channel activity of Orf3a/E based on increase in fluorescence induced by 4-aminopyridine, and this increase in fluorescence was inhibited by emodin and gliclazide. In 18 antigen/PCR positive samples, our test results found 15 are positive, demonstrating 83.3% concordance. In 24 antigen/PCR negative samples, our test results found 21 are negative, showing 87.5% concordance. Conclusions: We developed a cell-free, rapid, and high-throughput test that can detect Orf3a/E channel activity of SARS-CoV-2 in blood samples from COVID-19 infected individuals, which provides a likely explanation that the virus spreads to the heart via blood circulation.