The Role of Some Hematological, Immunological, and Coagulation Parameters in Predicting Bacteremia

Background: The diagnosis of sepsis is based on clinical and laboratory parameters that indicate the presence of infection and organ dysfunction. The most specific test for the diagnosis of sepsis is blood cultures, which are used to confirm the diagnosis of sepsis and identify the source of infection. Bacteremia is a serious condition that requires prompt identification and treatment. This study aimed to assess the hematological and immunological markers associated with bacteremia in patients presenting with fever of unknown origin. Aim: The objective was to evaluate and compare hematological and immunological parameters in patients with suspected bacteremia, to identify potential biomarkers for the condition. Methods: A cross-sectional study was conducted in Kirkuk city from July 1, 2023, to November 30, 2023. It included 141 patients over 18 years of age who were suspected of having bacteremia. Sepsis was diagnosed based on Sepsis-3 criteria, and blood cultures were performed. Key parameters measured included WBC, neutrophil counts, PTT/INR, IL-6, and CRP levels, among others. Results: Blood cultures revealed that 88 patients (62.4%) had positive results, indicating a significant prevalence of bacteremia. White blood cell (WBC) count, neutrophil count, and neutrophil-to-lymphocyte ratio (NLR) were significantly elevated in the positive culture group, suggesting their potential as markers for bacteremia. Immunological analysis revealed significantly higher levels of IL-6 and CRP in patients with positive cultures, further highlighting their utility as biomarkers. Additionally, coagulation parameters such as PT, PTT, and INR were notably higher in the positive culture group, indicating a more pronounced coagulation disruption. Among the 88 cases with positive cultures, Gram-negative bacteria were predominant, accounting for 81.81% of the isolates, underscoring the need for targeted antimicrobial therapy. Comparative analysis between Gram-positive and Gram-negative bacteremia showed higher inflammatory responses in the latter group, as indicated by elevated IL-6, WBC, neutrophils, and CRP levels. The Neutrophil-to-Lymphocyte Ratio (NLR) has a high level of discrimination between positive and negative blood cultures as a predictor of bacteremia, with a sensitivity of 75% and a specificity of 67.9%. An NLR above 1.144 is associated with a higher likelihood of positive blood culture results Conclusion: Elevated WBC, neutrophil counts, NLR, IL-6, coagulation parameters, and CRP levels are associated with positive blood cultures and may serve as useful biomarkers for bacteremia. These markers, particularly NLR, should be considered in the diagnosis and management of bacteremia.