High-resolution leukocyte analyzers: retrospective and prospective

Five leukocyte analyzers (three from the United States and two from Japan) entered commercial production during the decade 1974-1984; and three (all from the United States) entered pilot production, but were abandoned before complete commercialization. These instruments are automated microscopes, most of which have robotic capabilities in handling glass microscope slides. All incorporate machine vision computers for the purpose of performing multispectral image processing and pattern recognition. Since the objects which these machines must recognize (human white blood cells, red cells, and platelets) are small (from 2 to 20 micro in diameter) and have significant microscopic detail, the robotic manipulation of the microscope slide must be extremely precise, and the accompanying electrooptical imaging system must furnish submicron resolution. Today, these leukocyte analyzers worldwide analyze the cellular blood constituents of tens of thousands of patients per day. They gather clorimetric and morphometric data nabout one billion multispectral images per year and compute and report their analysis of this data. Unfortunately, the fiftymillion dollar investment made collectively by the business community has led to such a disappointing return that, as of 1986, all United States manufacturers have abandoned production. At the present time, only two machines are in production, both in Japan. This paper describes the historical evolution of these leukocyte analyzers and furnishes technical detail on the electrooptical characteristics of two major United States machines.