A Sex Difference in the Platelet Count

Abstract

A study of the platelet counts of 868 blood donors aged 18-65 showed a higher mean count in women than in men, the difference in the premenopausal age groups being highly significant (P9/l. The mean counts of women taking a contraceptive pill did not differ significantly from those who were not. Values for the normal platelet count in man quoted in most standard haematological texts are derived from studies made on relatively small numbers of individuals using visual counting techniques. The advent of automatic counting and data processing has made practicable the examination and evaluation of larger bodies of data with a relatively higher degree of precision than previously. This communication reports the results of such a study made on blood donors. The work was suggested by the finding of a significantly higher mean platelet count for women in the routine counts made selectively on a hospital population.