Technological advances introduced during the past two decades have resulted in availability at relatively low cost of a great variety of laboratory tests potentially useful in the clinical practice of perinatal medicine and pediatrics.
Recently, a remarkable expansion of possibilities for quantitative analysis of large numbers of individual cells has also been emerging. This new era of cell analysis was introduced in 1956 by Coulter's1 invention of a procedure for rapid and accurate sizing and counting of tens of thousands of individual cells per minute. For the first time, reliable automated quantitative analyses of large numbers of single human cells became possible.
In 1965, Fulwyler2 reported an ingenious coupling of the Coulter technique for cell volume determination ("sizing"), with a procedure for separating and recovering ("sorting") subpopulations of cells of different sizes from complex mixtures. His invention consisted of a means of isolating individual cells in a