Blood and its main components are commonly used to detect states of selenium deficiency. In order to examine whether human platelets are able to provide better or additional information, improvements of the analytical method resulted in surprisingly narrow normal ranges for selenium and other mineral elements using neutron activation analysis (NAA) and atomic absorption spectrophotometry (AAS), and controlling thermal neutron flux, (n, gamma)-cross sections, mean platelet wet wt, and water fraction of the platelets. Previously reported selenium concentrations in platelets on wet wt basis in the order of 500 ng/g--half of which had been found to derived from early bone marrow precursors using 74Se-selenite--were reproduced by NAA and AAS. However, with the new analytical method the selenium concentrations showed a narrower normal range than that of plasma. Moreover, platelet selenium did not in all cases correlate with plasma selenium. Cellular tissues such as platelets should, therefore, help to detect latent states of selenium deficiency.