Objective: COVID-19 is a very serious disease and is considered a pandemic by the WHO. The aim of this study is to determine the renal function and serum osmolality among COVID-19 patients in Khartoum state, Sudan.

Method: This is retrospective study was conducted in Gebra Hospital, Khartoum state, Sudan from April 2021 to August 2021. The study enrolled 50 patients with Covid-19 and 50 healthy individuals as a control group. After all the enrolled participants signed the informed consent the samples were analyzed for Creatinine, Urea, Sodium, and potassium. By using an A25 fully automated chemistry analyzer, and serum Osmolality  (mOsm / kg) was calculated according to Smithline and Gardner formula.

 Results: The study revealed a significant increase of the mean of Urea (P.value = 0.001), Creatinine (P.value = 0.001), however significant decrease in the mean of e GFR (P.value<0.05) on the first day of the admission. There was a significant increase in the mean of plasma Urea, Creatinine, and eGFR on the 7th day of admission when compared with the first day, P.value = (0.0001), (0.001), (0.001), respectively. The study revealed a significant difference in plasma Osmolality in COVID-19 patients (280.73 ±16.10 mOsm/kg) when compared with the control group (288.13 ±3.42 mOsm/kg), P.value = 0.0.

Conclusion: COVID-19 does not affect only the lungs; it can also affect the kidney. This study concluded that there were an elevated serum creatinine, blood urea, and low glomerular filtration, and there was a significant difference in serum osmolality in COVID- 19 than in the healthy group.

Keywords: COVID -19; Serum Osmolality; eGFR; Renal function; Sudan.