The ratio of immature to total neutrophil count may indicate the presence of a significant infection in a neonate.



(1) white blood cell count

(2) absolute total neutrophil count

(3) absolute immature neutrophil count


total absolute neutrophil count =

= (percent mature and immature neutrophils) * (white blood cell count per µL) / 100


ratio of immature to total neutrophil count =

= (absolute immature neutrophil count) / (absolute total neutrophil count)



• The ratio may range from 0 to 1.

• A normal neonate may show a ratio around 0.11 during the first 48 hours after delivery.

• An increase in the ratio may be present with an occult infection.

• A ratio > 0.8 indicates that there is depletion of the myeloid reserves within the marrow. This finding may precede death in a septic neonate.


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