TNF and COVID-19: Serum ferritin level was also significantly high in patients with vitamin D deficiency (319.17 ± 38.21 ng/mL vs 186.83 ± 20.18 ng/mL) than in patients with normal vitamin D. Serum TNFα level (in pg/mL) was also high in vitamin D deficient COVID-19 patients (13.26 ± 5.64 vs 11.87 ± 3.15) but the difference was not significant (Table 3).