The band count imprecision – a Croatian multicentric pilot study

Abstract

Graphical abstract Highlights • Band counting is unreliable practice due to the high inter-observer variability • 2015 International Council for Standardization in Haematology guidelines recommend to count band neutrophils as segmented neutrophils • The inclusion of bands within the white blood cell differential is still used in Croatia • There is a very high variability in enumerating bands among Croatian laboratories • There is a need for national recommendations that will endorse ICSH guidelines IntroductionDue to high inter-observer variability the 2015 International Council for Standardization in Haematology (ICSH) recommendations state to count band neutrophils as segmented neutrophils in the white blood cell (WBC) differential. However, the inclusion of bands as a separate cell entity within the WBC differential is still widely used in hematology laboratories in Croatia. The aim of this multicentric study was to assess the degree of inter-observer variability in enumerating band neutrophils within the WBC differential among Croatian laboratories. Materials and methodsSeven large Croatian hospital laboratories from different parts of the country participated in the study. In each of 7 participating laboratories, one blood smear, that was flagged by the analyzer as possibly having bands, was evaluated by all personnel participating in the analysis of hematology samples. Between-observer manual smear reproducibility was expressed as coefficient of variation (CV) and calculated using the following formula: CV (%) = (standard deviation (SD)/mean value) x 100%. ResultsThe CVs (%) and relative band neutrophil counts in participating laboratories were as follows: 15.4% (16-24), 19.2% (16-32), 19.5% (17-40), 21.1% (17-44), 35.0% (8-26), 51.9% (3-29), and remarkably high 62.4% (12-59). For segmented neutrophils CVs were lower, ranging from 7.4% to 32.2%. The CVs did not correlate with the number of staff members in each hospital (P = 0.293). ConclusionsThis study revealed very high variability in enumerating band neutrophil count in the blood smear differential among all participants, thus prompting a need for action on a national level.