Qualitative changes of white blood cells and perinatal diagnosis of infection in high-risk preterm infants.

A total of 60 preterm infants, aged less than 37 weeks of gestation were studied. Morphological changes of polymorphonuclear neutrophils (PMN) were evaluated in two groups of patients. PMN vacuolization was frequently noted at birth in preterm neonates with culture-proven infection (sensitivity 86%, specificity 90%). Toxic granulations were a less reliable indicator of bacterial infection. A relatively good correlation with other parameters in use for "sepsis screen" we found with band cell/total neutrophil ratio (X2 = 1.66, P greater than 0.1). Examination of peripheral blood smears for vacuolization of WBCs appears to provide adjunct in the early detection of bacterial infection in preterm babies.