TNNI3 and COVID-19: In COVID-19 patients, plasma creatinine, plasma urea nitrogen (PUN), cystatin C, high-sensitivity cardiac troponin I, creatine kinase (CK), creatine kinase isoenzymes (CKI), myoglobin, lactate dehydrogenase (LDH), and N-terminal pro B-type natriuretic peptide (NT-proBNP) were higher than the upper normal limit, while the estimated glomerular filtration rate (eGFR) was lower than the lower normal limit (Table 1).