The automated differential; pattern recognition systems, precision, and the spun smear.

Utilizing normal patient blood samples, two automated differential pattern recognition systems, the ADC-500 and the Hematrak 360, were compared in a duplicate study with the manual eye method, using spun and wedge smear preparations. The study showed a superior precision for the 500-cell differential, but occasional data points with spun smears were unusually drifted from the central cluster for both the manual and instrument methods. Analysis of the data uncovered at least two reasons for these unusual outliers: "star artifacts" and warped glass slides. The importrance of these method-related artifacts are discussed, alo ng with the future of the 500-cell differential with today's automated technology.