A Narrative Review of the Evaluation of Biomarkers in COVID-19 Patients Indicating the Course of the Disease

The global spread of the severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) virus has led to a widespread outbreak of coronavirus disease-2019 (COVID-19), resulting in a pandemic. Following the end of the pandemic, COVID-19 has transitioned into an endemic phase characterized by anticipated periodic surges. Therefore, the development of readily available prognostic biomarkers for COVID-19 patients continues to be a crucial field of study. Monitoring of blood biomarkers for patients with COVID-19 is a crucial component of patient care. Therefore, it is necessary to conduct hematological assessments such as leukocyte count, lymphocyte count, neutrophil count, neutrophil-lymphocyte ratio, and thrombocyte count. Additionally, inflammatory markers such as C-reactive protein, erythrocyte sedimentation rate, and procalcitonin should be measured. Immunological indicators including interleukin-6 and tumor necrosis factor-α should also be evaluated. Furthermore, biochemical tests such as aspartate aminotransferase, alanine aminotransferase, urea, creatinine, and troponin levels should be assessed. Lastly, coagulation parameters such as D-dimer, fibrin degradation products, and fibrin levels should also be examined. The objective of this narrative review is to assess blood biomarkers that have the potential to be valuable in monitoring the progression and management of COVID-19. Studies published between 2020 and 2023 and scanned in PubMed, Ebsco and Google Scholar were used in the analysis. Keywords such as ''COVID19'', ''SARS-CoV2'', ''biomarkers'' and ''severe SARS-CoV-2 infection'' were used to restrict the search.