Expected ranges for blood neutrophil concentrations of neonates: the Manroe and Mouzinho charts revisited.

BACKGROUND

Upper and lower reference limits for blood neutrophil concentrations of neonates were reported by Manroe, Rosenfeld and co-workers in 1979 and by Mouzinho, Rosenfeld and co-workers in 1994. Studies by Carballo and co-workers and Maynard and co-workers suggested that at high altitude a much higher upper limit of values occurs, and that neutrophilia is often diagnosed inappropriately, at high altitude, if the Manroe and Mouzinho charts are used.

STUDY DESIGN

We revisited the Manroe and Mouzinho charts using modern cell counting instrumentation and very large sample sizes. This was accomplished with data from an 18-hospital health-care system, at hospitals averaging 4,800 feet above sea level. Data were obtained from neonates in the first 10 days following birth, using tests performed on a single type of automated blood cell counter (Beckman Coulter LH 750, Fullerton, CA, USA). To obtain a description of 'expected values,' patients with the following diagnoses, known to have a high proportion of abnormal neutrophil counts, were excluded from the analysis; (1) maternal pregnancy-induced hypertension, (2) early-onset bacterial sepsis, (3) a discharge diagnosis of congenital neutropenia and (4) trisomy 21, 18 or 13.

RESULT

Blood neutrophil concentrations were tabulated from 30 354 tests performed on neonates of 23 to 42 weeks gestation, with dates of birth between 1 January 2004 and 31 May 2007. The reference range charts generated from these data have much higher upper value limits than do the Manroe and Mouzinho charts, and are similar to the high-altitude reports of Carballo and co-workers and Maynard and co-workers. Neonates whose mothers labored before delivery had significantly higher neutrophil counts (averaging 3,500 neutrophils per mul higher, P<0.0001; comparing cesarean section deliveries with vs without labor). Females had significantly higher counts (averaging 2,000 neutrophils per mul higher) than males (P<0.0001). Counts did not differ on the basis of racial/ethnic group.

CONCLUSION

The figures of this report describe the expected ranges for blood neutrophil concentrations over the first 10 days of life among neonates of 23 to 42 weeks gestation at high altitude.