Abstract

The authors aimed to develop a tool to assess total cell numbers in a microscope's field of vision, which would provide the denominator for calculating the percentage of positive cells for a given antigen in bone marrow trephine biopsies (BMTBs) of varying cellularities. Precise estimates of cell densities were made from 179 images of BMTBs of varying cellularities using a cell-counting software. The estimates were then validated on an independent set of 20 BMTBs. Among the 179 images, there was a strong linear association between marrow cellularity and cell numbers (Pearson correlation: 0.788). Then standardised cell densities (cells/mm² of bone marrow) were deduced for BMTBs of varying cellularities. In the validation study, the actual and the estimated cell numbers correlated strongly (Pearson correlation: 0.990). The cell density estimates provided in this study can be adapted for any microscope and the same method can be used for calculation of the percentage-positive cells for any antigen.