With the conventional methods used in current practice, the results of human granulocyte motility assays are expressed by a numerical value that defines the leading front of cells into micropore filters. The authors have developed a fast procedure which allows the complete curve of polymorphonuclear leukocyte (PMN) migration to be obtained, from the initial plane of a filter to the maximum propagation depth. In this way, more information is given than that expressed by a single parameter. The paper describes the procedure used to determine the normality curves both for random and stimulated migration, according to a simple model which defines the PMN propagation in micropore filters. A normality band that defines variations due to the stochastic process is also reported.