ABSTRACT
Because of high mortality and long-term hospital stay among patients with SARS-CoV-2 infections, it is important to search for biochemical changes in different organs and systems that could be useful in diagnosis and prognosis of COVID-19. We conducted a literature search of online databases including PubMed, Web of Science, Scopus and Google scholar for relevant materials on biochemical changes in SARS-COV-2 infections published between December 2019 and March 2021. The review shows that SARS-COV-2 uses the angiotensin converting enzyme 2 (ACE2) for attachment and entry into host cells. These ACE2 are abundantly expressed by the epithelial cells of the respiratory tract and moderately expressed by the epithelial cells of the esophagus, stomach, duodenum, ileum, rectum, cholangiocytes, liver hepatocytes, pancreatic beta cells, and kidney tubular cells. This explains the systemic nature of SARS-COV-2 infection, and the high morbidity and mortality associated with COVID-19. Although, tests to assess biochemical changes are not specific enough for the diagnosis of SARS-CoV-2 infection, they may be useful for predicting outcome of COVID-19. This review highlights biochemical parameters that are significantly elevated or reduced in SARS-COV-2 infections, and which can be used as predictive factors of the severity and prognosis in COVID-19 patients.