An evaluation of the differential from the Abbott CD 3500 in a population of patients with haematological abnormalities.

The Cell Dyn 3500 (CD 3500) Haematology Analyser (Abbott Diagnostics, Lane Cove, NSW, Australia) has been evaluated to determine the reliability of the differential and white cell suspect flagging in a population of patients with known haematological abnormalities. The evaluation included the assessment of white cell differential parameters in addition to sensitivity, specificity and efficiency of white cell suspect flagging. The study showed that the CD 3500 is an efficient and sensitive screening tool for detecting the presence of clinically significant white cell abnormalities. Generally, the Blast and Band flags demonstrated the highest level of false positive flagging (lowest sensitivity). The immature granulocyte flag was found to be an extremely reliable indicator of the presence of myelocytes, metamyelocytes and promyelocytes on the film. There was a 0.4% false negative rate where significant numbers of variant lymphocytes (> 10%) were not detected by the CD 3500 on flagging alone. When analyser flags and white cell scatter distribution are considered in combination with defined laboratory limits, all white cell suspect flags have acceptable sensitivity, specificity and efficiency rates.