Delta Immature Platelet Fraction Is Associated With Mortality in Bacteremia Patients.

Objectives: Immature platelet fraction (IPF) for differentiating bacteremia has been explored, whereas its prognostic correlation remains uncertain. This study aims to confirm the predictive capability of IPF for bacteremia and investigate its association with prognosis.

Methods: Patients with complete blood count (CBC) on the blood culture day (D1) and the preceding day (D0) were retrospectively recruited and categorized into bacteremia and nonbacteremia groups. Immature platelet (IP) analysis, alongside CBC, was conducted. Delta IPF, defined by the absolute values of D1 minus D0 results was calculated. The ability to distinguish bacteremia from nonbacteremia patients, and the correlation with mortality were analyzed.

Results: From February to December 2020, a total of 150 patients were enrolled, with 75 having bacteremia. The specificity for delta IPF ≥3.4% to predict bacteremia was 97.3% (95% confidence interval [CI]: 90.7-99.7). When delta IPF ≥3.4% combined with procalcitonin ≥0.5 (ng/mL), the sensitivity was 90.5% (95% CI: 69.6%-98.8%). Within the bacteremia group, delta IPF and the proportion of patients with delta IPF ≥1.5% were significantly higher in nonsurvival, while delta platelet levels did not. Furthermore, delta IPF ≥1.5% was independently associated with 30-day mortality (adjusted odds ratio: 3.88, 95% CI: 1.2%-11.4%; p = 0.020). The 30-day survival curve demonstrated a significant difference between patients with delta IPF ≥1.5% and those without (p < 0.001).

Conclusions: Delta IPF correlates with mortality in bacteremia patients. Our findings suggest IPF not only helps detect bacteremia but also predicts prognosis in the early stage.