Blast flagging with the UniCel DxH 800 Coulter Cellular Analysis System

We recently conducted a series of evaluations of the new UniCel DxH 800 Coulter Cellular Analysis System at Barnes-Jewish Hospital in St. Louis, Missouri. This report addresses issues relating to the flagging performance of the DxH 800, especially as it relates to the detection of blast cells. The DxH 800 was designed with major performance and hardware enhancements over the previous LH series analyzer. Capturing 29 individual measurements per cell analyzed, the system provides improved sensitivity and specificity, which means more reliable assessment of abnormal cell populations. We undertook these particular studies to assess these enhancements and to evaluate the analytical performance of the DxH 800's automated white blood cell differential and flagging of abnormal blood samples. Our studies placed specific emphases on the detection of blast cells. The Initial evaluation of the ability of the DxH 800 to flag blast cells was remarkable. We ran 95 samples containing > or =1% blasts on both the Beckman Coulter LH 750 and DxH 800 instruments. Whereas the LH 750 had a 6.4% false-negative rate, the DxH 800 had a 0.0% false-negative rate. We then conducted an extensive study of 435 blast-positive samples on the LH 750, 302 of which were analyzed on the DxH 800 and 94 of which were analyzed on Siemens' ADVIA 2120 Hematology System. With a 0.3% false-negative rate, the DxH 800 outperformed the LH 750, which had a 9.6% false-negative rate. In a previous study of 311 random patient samples, the overall success rate of the DxH 800 in detecting abnormal samples in a mixed population of samples resulted in fewer false negatives (3 versus 6) and significantly fewer false positives (60 versus 152) than the LH 750. The lower rate of false positives for the DxH 800 dramatically reduced the number of unnecessary smear reviews that otherwise would have to be run on the LH 750. The DxH 800 has demonstrated that it is capable of reducing the number of unnecessary differentials performed, while performing better at detecting samples with abnormalities, particularly when blast cells are present.