ABSTRACT Objective Leukocytosis is often observed among children presenting with diabetic ketoacidosis (DKA). This study compares detailed parameters of leukocytosis in children presenting with DKA versus infection. Subjects and methods In this comparative cohort study, we collected data from two groups of children, one hospitalized with DKA and another with community-acquired pneumonia (CAP). The primary objective was to compare the neutrophil-to-lymphocyte ratio (NLR) between the groups. Total leukocyte count (TLC), absolute neutrophil count (ANC), platelet-to-lymphocyte ratio (PLR), and platelet-to-monocyte ratio (PMR) were also compared. The correlation of these hematological parameters with the clinical outcomes in the DKA group was also explored. Results Data from 35 children with DKA (mean age 7.4 years, 12 boys) and 40 children with CAP (mean age 7.9 years, 15 boys) were available for comparison. No significant NLR difference was observed between the DKA and CAP groups. Similarly, no significant difference was observed in TLC and ANC between the groups. However, significant differences between the DKA and CAP groups were observed regarding mean (standard deviation) PLR (108.26 [67.51] versus 166.60 [163.83], respectively, p = 0.01) and mean PMR (1,795.40 [4,307.00] versus 886.33 [1,726.41], p = 0.01). Among children with DKA, ANC and PMR correlated positively and hemoglobin level correlated negatively with unfavorable outcomes. Conclusions Specific parameters of leukocytosis (PLR and PMR) differed significantly in children with DKA versus CAP. Some widely available and inexpensive hematological parameters of inflammation (hemoglobin, ANC, and PMR) may predict outcomes in patients with DKA. . (DKA) infection communityacquired community acquired (CAP) neutrophiltolymphocyte lymphocyte (NLR TLC, , (TLC) (ANC) platelettolymphocyte platelet PLR, (PLR) platelettomonocyte monocyte (PMR compared explored 3 74 7 4 7. years 1 boys 79 9 comparison Similarly However standard deviation 108.26 10826 108 26 (108.2 67.51 6751 67 51 [67.51 16660 166 60 166.6 163.83, 16383 163.83 163 83 [163.83] respectively 0.01 001 0 01 1,795.40 179540 795 (1,795.4 4,307.00 430700 307 00 [4,307.00 88633 886 33 886.3 1,726.41, 172641 1,726.41 726 41 [1,726.41] 0.01. hemoglobin, (hemoglobin (DKA (CAP (TLC (ANC 108.2 1082 10 2 (108. 67.5 675 6 5 [67.5 1666 16 166. 1638 163.8 8 [163.83 0.0 1,795.4 17954 (1,795. 4,307.0 43070 30 [4,307.0 8863 88 886. 17264 1,726.4 72 [1,726.41 108. (108 67. [67. 163. [163.8 0. 1,795. 1795 (1,795 4,307. 4307 [4,307. 1726 1,726. [1,726.4 (10 [67 [163. 1,795 179 (1,79 4,307 430 [4,307 172 1,726 [1,726. (1 [6 [163 1,79 17 (1,7 4,30 43 [4,30 1,72 [1,726 ( [ [16 1,7 (1, 4,3 [4,3 [1,72 [1 1, 4, [4, [1,7 [4 [1,