The laboratory results pointed out that patients with long COVID symptoms also had a lower rate of red blood cells (RBC) [4.4 vs. 4.6 × 106/uL; p = 0.01]; a higher level of glucose [92 vs. 90 mg/dL; p = 0.03]; a lower glomerular filtration rate (GFR) estimate by Modification of Diet in Renal Disease (MDRD) [88 vs. 95; p = 0.03]; and a higher level of hypersensitive cardiac Troponin T (hs-cTnT) [6.1 vs. 3.9 pg/mL; p = 0.04]. This evidence concerns the gene TNNT2 and kidney disorder.