A bstract Introduction The measured D-dimer levels in coronavirus disease-2019 (COVID-19) patients have no specific cutoff to find the progression of coagulopathy and severity. Aim This study aimed to determine prognostic cutoff values of D-dimer for intensive care unit (ICU) admission among COVID-19 patients. Materials and methods This cross-sectional study was conducted in Sree Balaji Medical College and Hospital, Chennai, during a period of 6 months. This study included 460 COVID-19-positive individuals. Results The mean age was 52.2 ± 12.53 years. Patients with mild illness have D-dimer value 461.8 ± 221, whereas moderate and severe COVID illness patients have D-dimer values of 1915.2 ± 699.9 and 7937.6 ± 2045.2, respectively. D-dimer cutoff value of 1036.9 is shown to be a prognostic cutoff value for COVID-19 patients admitted in the ICU with 99% sensitivity and 17% specificity. The area under curve (AUC) was considered excellent (AUC = 0.827, 95% Cl: 0.78–0.86, p -value < 0.0001) indicative of high sensitivity. Conclusion The D-dimer value of 1036.9 ng/mL was found to be the optimum cutoff for the patients to predict the severity of the COVID-19-positive patients admitted in the ICU. How to cite this article Anton MC, Shanthi B, Vasudevan E. Study to Determine a Prognostic Cutoff Values of the Coagulation Analyte D-dimer for ICU Admission among COVID-19 Patients. Indian J Crit Care Med 2023;27(2):135–138.