Evaluation of the Hematrak differential leucocyte counter

The main objectives of the evaluation were to: (1) assess accuracy and precision of cell recognition, (2) establish 'reference ranges' and compare with existing ranges, (3) assess machine reliability and suitability for normal working patterns. The accuracy and precision of the instrument were found to be acceptable, within the limits imposed by counting 100 cells in a wedge smear. Reference ranges compared well with established ranges with the exception of monocytes and eosinophils. the instrument was initially evaluated over a 12-week period and has been in routine use for 18 months durng which time it has been found to be very reliable. It has fitted in with the laboratory working patterns without causing any changes in work flow.