Reference intervals for circulating nucleated red blood cell counts of neonates, improved by the refineR algorithm

A "high" concentration of nucleated red blood cells (NRBC) in the blood of neonates at birth has been used as a biomarker of fetal hypoxia and a risk factor for poor outcome. Previous neonatal reference intervals for NRBC counts were likely contaminated by high counts from neonates born after unrecognized fetal hypoxia. We hypothesized that a new method for creating reference intervals, refineR, would produce more accurate physiological intervals for neonatal NRBC counts.

We utilized refineR and real-world multicentered data from Intermountain Health to create new neonatal NRBC count reference intervals.

Using 4 ½ years of multi-hospital data, refineR created reference interval charts for NRBC counts at birth and over the first days. The new intervals are narrower than the previous version, with lower median and upper-limit values.

With the new charts, clinicians can more confidently assess whether a neonate's NRBC count is normal vs. elevated.