Diagnostic performance: a comparative study of the leukocyte differential count on four automated haematology analysers.

The diagnostic performance of the haematology analysers, Technicon H1, Sysmex NE 8000, Coulter STKS and Sequoia Cell Dyn 3000 was determined by comparing their results for automated differential counting with the result obtained for 400 cells by the manual microscopic method. These comparative studies were performed on a group of adults, containing both normal individuals (n = 150) and those affected by various pathologies (n = 113). The number of morphologically false negatives is low for all the systems (from 1.8% for the Cell Dyn 3000 to 6.2% for the NE 8000), while the number of distributionally false negatives was slightly higher (from 4.4% for the Cell Dyn 3000 to 7% for the H1 and NE 8000). The morphological flags, though useful for improving the diagnostic performance of the instruments, show a rather modest sensitivity when taken individually: immature granulocytes/bands from 71% for the STKS to 43% for the NE 8000; blasts from 66.6% for the H1 to 53.3% for the STKS, atypical lymphocytes from 59% for the H1 to 13.6% for the NE 8000; erythroblasts from 42.8% for the STKS to 7% for the NE 8000.