Use of Standard Neutrophilic Reference Values for Prediction of Sepsis in ≤800 Gram Birth Weight Infants

The neutrophilic reference limits developed by Manroe et al. (J Pediatr 95:89-98, 1979) have been widely utilized in the evaluation of neonates with possible bacterial infection. To assess the utility of these limits in extremely low birth weight (ELBW) infants we reviewed data from 124 infants with birth weights ≤800 g. Neutrophil values from non-infected infants were outside of reference limits for 71% of total neutrophil counts, 47% of immature neutrophil counts, and 75% of immature to total neutrophil ratios. Neutrophil values from infected infants did not differ from those of non-infected infants. The majority of ELBW infants in the first 24 hours of life have neutrophil values outside of published normal values and thereby suggestive of infection. Neutrophilic values alone should not be used as a guide for treatment decisions.