Discrepancy in conventional microscopic manual differential counts of band neutrophils among microscopists

The interpretation of the band neutrophil count on manual differential counts performed amongst microscopists can vary greatly. The band neutrophil is an immature granulocyte, maturing towards a segmented neutrophil. There are varying degrees of misconception of the band neutrophil identification, as the band neutrophil closely resembles the maturing segmented neutrophil. Although there are guidelines for the identification of band neutrophils, many laboratories incorporate their own “standard” as to what a band neutrophil should look like. Even when a standard exists for the identification of band neutrophils, many microscopists still have difficulty identifying these cells, making it difficult to accurately perform, interpret and report a manual differential count. Due to the controversy it is thus necessary to identify whether the problem lies with the identification of the band neutrophil itself, or the individual microscopist’s perception of differentiation between the band neutrophil and a maturing segmented neutrophil. The purpose of this study was to establish the accuracy by which microscopists distinguish band neutrophils from mature segmented neutrophils, the extent of discrepancies in the band neutrophil count amongst microscopists, to establish whether microscopists required re-training and to establish meaningful recommendations for microscopists to aid in the accurate identification of band neutrophils. The researcher thus made use of a self-administered picture diagram, distributed among microscopists to assess the accuracy of the band neutrophil counts prior to training. Participants counted an average of 61.47% neutrophils and 38.53% band neutrophils. Coefficient of variation (CV) for neutrophils and band neutrophils were calculated and yielded a CV of 22.48 and 35.87 respectively. Due to the high CV calculated, suggesting a greater level of dispersion around the mean, the researcher investigated individual responses from the picture-diagram. With the findings of the individual picture-diagram results, the researcher developed an impression that there was a large variation in counts for both neutrophils and band cells. Training was then given to participants arranged by the researcher, for accurate band neutrophil identification. Following training a second survey was conducted in order to assess the variation in counts among microscopists. 1 The peripheral blood smear was then provided and used to perform a manual differential count by conventional light microscopy, in order to compare results. Similarly, results obtained by the microscopists was compared to the verified manual differential count performed by a Haematologist; to improve the accuracy of results reported routinely. With the findings of the individual manual differential count results the researcher observed, that there was indeed a discrepancy in the manual differential counts performed by microscopists