EVALUATION OF MONOCYTE COUNTING WITH 2 AUTOMATED INSTRUMENTS BY THE USE OF CD14-SPECIFIC IMMUNOMAGNETIC DYNABEADS(R)

Accurate determination of monocytes can be a problem with automated ha ematological analysers as well as with visual microscopy. We have comp ared monocyte counts from our two routine automated instruments, Techn icon H1 and Sysmex NE-1500. In the NE-1500 the monocyte counts appear to increase with increasing concentrations of neutrophils, compared w ith the H1 results. The accuracy of the monocyte counts was assessed using Dynabeads(R) M-450 CD14. These uniform magnetizable polystyrene beads coated with monoclonal antibody specific for CD14 membrane antig en isolated monocytes from the blood samples. The influence of this de pletion on the monocyte counts and histograms from the two instruments and by visual microscopy were compared. On average 90% of the monocyt es counted by visual microscopy were removed from six blood samples. I n the same samples the beads removed an average of 75% of cells identi fied as monocytes by the H1 but only 49% of those identified as monoc ytes by the NE-1500. These Dpnabeads(R) can be a useful tool in evalua ting monocyte identification in different haematological situations an d for manufacturers developing technology for automated leucocyte diff erential counting.