in a total of eleven determinations with hematocrits spun for 30 minutes, plasma trapping varied between 3.65 and 5.33 per cent (mean 4.35 per cent, standard
deviation 0.62 per cent) coefficient of variation 14.2 per cent. However, when centrifugation was continued for 55 minutes instead of 30 minutes, a much smaller variation between one sample and another was found.