Automated counting of white and red blood cells in the cerebrospinal fluid.

The objective of this study was to examine to what extent the automated method of the Bayer H*2 instrument could replace the visual counting of white and red blood cells in cerebrospinal fluid. The number of white blood cells as well as the percentage of mononuclear and polymorphonuclear cells were counted in the 'Baso channel' (Research screen 3) whereas the number of red cells were registered as the 'R-count' (Research screen 1). All automated cell counts were compared to visual estimates. The automated count yielded reliable results down to 5 x 106 white blood cells/l and 5 x 108 red blood cells/l. In some samples 'noise' was present in the Baso channel. A correct white blood cell count could then be obtained by counting the cells directly as dots on the screen. It was possible to differentiate between polymorphnuclear cells and mononuclear cells at all WBC concentrations. The automated counting of cerebrospinal fluid can be performed without changing thresholds or sample volumes of the instrument. Thus, in the routine practice it will be possible to alternate between automated counting of whole blood samples and cerebrospinal fluid samples.