Comparing automated vs manual leukocyte differential counts for quantifying the ‘left shift’ in the blood of neonates

Objective:the neutrophil ‘left shift’ can be measured via the immature to total (i/t) neutrophil ratio or the absolute bands per μl using a manual differential count. it can also be measured from an automated differential count by the immature granulocyte percentage (ig%) or the absolute ig per μl. in neonates, it is unknown if the manual or automated differential count is superior.study design:we directly compared complete blood counts (cbcs) with manual and automated differential counts from infants <90 days old, and documented whether or not each neonate was infected. we developed reference intervals for i/t ratio, bands per μl, ig% and ig per μl using values from non-infected neonates.results:the database had 10 714 cbcs. the upper reference interval for i/t ratio was 0.29 in the first 48 h and 0.31 thereafter; bands per μl was 3710 μl−1 in the first 48 h and 1785 μl−1 thereafter. ig% was 6.2% then 4.2%; ig per μl was 1460 μl−1 then 613 μl−1. statistical performances of the four methods were equivalent for identifying infection.conclusions:we developed reference intervals for four methods of quantifying a neonate’s ‘left shift’. the information from automated differentials is not inferior to that from manual differentials in identifying infections, but automated differentials have the advantages of a larger sample size, being less expensive, and faster performance times.