Establishing the correct diagnosis of the clinical stage and the severity of dengue patients is very important to determine the prognosis. Examination of platelets, hematocrit and leukocytes for each clinical stage of dengue can help group and manage patients based on their clinical degree. This study aimed to determine the relationship between platelet, hematocrit and leukocyte examination results with the clinical degree of dengue based on WHO. This study used a cross-sectional study design with a sampling technique using consecutive sampling from July-November 2020 in 5 hospitals at Bengkulu City with total sample of 35 patients. The results found a strong relationship between hematocrit levels and the degree of severity of dengue (p = 0.001; r = 0.637). However, there was no significant relationship between the number of platelets (p = 0.826; r = -0.039) and leukocytes (p = 0.554; r = -0.103) with the severity of dengue. Laboratory tests are crucial to establish the clinical degree of dengue and disease’s prognosis.