In this study a protocol for blood serum analysis was defined and the concentrations for Br, Ca, Cl, Fe, Na, Rb, Se and Zn
were obtained by instrumental neutron activation analysis. Blood samples were collected from healthy elderly volunteers who
were selected based on the SENIEUR protocol. Contamination of blood by the collection procedure was also evaluated and found
negligible. The serum was separated by centrifugation, then freeze-dried and analyzed. Most of results obtained were within
the acceptable value ranges used by physicians for normal population. The certified reference material, NIST SRM 1566b Oyster
Tissue was analyzed for quality control.