Immature platelet fraction in predicting sepsis in critically ill patients

To establish whether in critically ill patients without sepsis at intensive care unit (ICU) admission the percentage immature platelet fraction (IPF%) is a cellular marker predicting sepsis to verify a possible correlation between IPF% changes and manifest sepsis and describe the IPF% time course after ICU admission.

Prospective, observational 7-day study of 64 adult patients admitted to a general ICU at a University Hospital with no sepsis criteria. We measured daily IPF%, procalcitonin (PCT), C-reactive protein, platelets, white blood cell count and coagulation variables. Thirty-one patients with sepsis at ICU admission were studied as controls.

The only variable we tested at ICU admission that predicted sepsis was plasma IPF% (p < 0.001; >4.7 %: sensitivity 56.2 % IC 37.7-73.6; specificity 90.0 % IC 73.4-97.8). IPF% and PCT values were higher for the patients who had sepsis at admission and during the study than in patients in whom sepsis never developed (IPF%: p = 0.017; PCT: p = 0.030). Among the outcome variables, logistic regression was identified as the only variable related to the development of sepsis, IPF% (r = 0.51; p = 0.004). In patients who developed sepsis IPF% was inversely correlated with platelet count (r = -0.60; p < 0.001) and had high values before sepsis became manifest, decreasing significantly on the 2nd day thereafter.

In patients without sepsis at ICU admission IPF% increases before sepsis becomes manifest. Measuring IPF% through an easily available technology can therefore provide an early cellular marker predicting the development of sepsis.