Variability of in vitro migration of human leucocytes.

A comparison of the capillary method (CM) and the agarose microdroplet method (AMM), using the same materials, for measurement of human leucocyte migration in vitro yielded similar large degrees of variability. Between fifteen and twenty-six replicate cultures were established for each method in fourteen subjects The range of the coefficients of variation were .7-28.8% (CM) and 7.2-19.3% AMM). Most of 115 publications reviewed describe only three or four replicates. Their results relating to host responses in the fields of cancer, tissue transplantation and several chronic diseases should be interpreted with regard to the variability of the system. The use of human leucocyte migration in vitro for any purpose should incorporate more stringent statistical control of sample size than has been customary. The use of two standard statistical formulae is proposed as this control.