The HemoCue WBC DIFF system could be used for leucocyte and neutrophil counts but not for full differential counts

The aim of this study was to evaluate the HemoCue WBC DIFF system for point of care testing of fingerstick samples from paediatric patients.

We analysed 158 white blood cell counts on both the point of care HemoCue WBC DIFF instrument and the Cell Dyn Sapphire cell counter used by our central laboratory and compared the results. The measurements were performed using fingerstick samples drawn by nurses working in paediatric emergency and paediatric oncology units.

There was good agreement between the two instruments for white blood cell and neutrophil counts. The correlation was weaker for lymphocytes, and the correlations were poor for monocytes and eosinophils. The HemoCue WBC DIFF flagged 56 of the 148 capillary drawn samples as abnormal, but none of the 10 venously collected samples. Only two of the flagged samples differed significantly between the instruments, with regard to the cell counts.

The correlations between the white blood cell counts and neutrophil counts in this real-life study were good enough to diagnose children in emergency department and oncology unit settings. However, the high number of pathological flags from fingerstick samples, which made reruns necessary, limited the usefulness of the instrument.