Evaluation of the predictive performance of CD64 and CD69 markers in the early diagnosis of bloodstream infections

BACKGROUND: Bloodstream infection (BSI) is a leading cause of global morbidity and mortality. This study aimed to evaluate the predictive performance of CD64 and CD69, together with other cell surface markers, for early diagnosis of BSI and to compare them with conventional inflammatory markers. METHODS: Expression levels of neutrophil and monocyte CD11b, CD14, CD64, and CD69 were measured by flow cytometry. Procalcitonin, C-reactive protein-to-albumin ratio, sTREM-1, calprotectin, and hematological ratios were also analyzed. Diagnostic performance was assessed using ROC analysis, and logistic regression, including Firth penalization, was performed to identify independent predictors of BSI. RESULTS: < 0.05). CONCLUSION: Cell surface markers, particularly mCD69, demonstrated good discriminatory performance between BSI and control groups. Their combined use with conventional markers may provide useful complementary information; however, future validation studies including alternative comparator groups are required before routine clinical implementation.