Do the flags related to immature granulocytes reported by the Sysmex XE-5000 warrant a microscopic slide review?

OBJECTIVES The Sysmex XE-5000 instruments (Sysmex, Kobe, Japan) count immature granulocytes (IGs) and use the "Imm Gran?" flag to signal unreliable results. This study investigated the usefulness of the "Imm Gran?" flag and the analytical and diagnostic performance of the IG measurements in a side-by-side evaluation. METHODS In total, 408 samples were analyzed on three XE-5000 instruments. The IG count and the "Imm Gran?" flag reports from all three instruments were used for reproducibility studies. The diagnostic performance of the automated IGs and the "Imm Gran?" flag were studied by comparing the XE-5000 results with the results of the manual differential. RESULTS The reproducibility of the "Imm Gran?" flagging between instruments was poor (қ, 0.75-0.80). The most significant contributor to the report of the "Imm Gran?" flag was bands, and the flag played a minor role in detecting blasts. The interinstrument reproducibility of the IG counts was high (intraclass correlation, 0.99). The IG count reported by XE-5000s was higher than the manual IG count (36%-55%), and the difference and the variability tended to increase with increasing levels of IGs. CONCLUSIONS The "Imm Gran?" flag has a poor analytical quality and gives no substantial information on the presence of blasts in the sample. We therefore suggest reporting the automated IG count without initial microscopic slide review.