Platelet-to-Lymphocyte Ratio-A Real or Fake Bridge Between Inflammation and Coagulation in COVID-19 Patients: A Scoping Review.

Publication date: May 13, 2026

Background: Patients with COVID-19 often develop COVID-19-Associated Coagulopathy (CAC)-an imbalance between procoagulant and anticoagulant pathways resulting from the uncontrolled inflammatory response triggered by SARS-CoV-2 infection. This study aims to investigate the impact of a hematological and inflammatory parameter-the platelet-to-lymphocyte ratio (PLR)-on the severity and mortality of COVID-19. Methods: We conducted a comprehensive search of the PubMed database and yielded 75 articles published in the period of 2020-2025, of which 20 studies that evaluated the prognostic value of PLR on hospital admission in COVID-19 patients were included. The review particularly focuses on ROC analyses and reported AUC values. Results: A total of 20 studies were analyzed, including 13 studies assessing disease severity and 14 studies evaluating mortality. Higher PLR values have been observed in patients with a more severe course of COVID-19 compared to those with milder disease, and in non-survivors compared to survivors. However, the literature shows inconsistency regarding the diagnostic utility of PLR based on ROC curve analysis. The reported AUC values ranged from 0. 559 to 0. 811 for disease severity differentiation and from 0. 474 to 0. 758 for mortality, which may be related to the heterogeneity of the study populations included in the analysis. Conclusions: PLR may not serve as a direct bridge between inflammation and coagulation in COVID-19-Associated Coagulopathy, but it is indirectly linked to disease severity and mortality, as it reflects changes in both platelet and lymphocyte counts. It is a complementary marker that may assist clinicians in assessing COVID-19 patients but still requires further investigation.

Semantics

Original Article