Kuwahara S S, Rasmussen L W
Am J Med Technol. 1976 Jul;42(7):255-8.
A comparative analysis performed in late 1974 revealed that a cyanmethemoglobin secondary standard prepared by the laboratory at the Michigan Department of Public Health in 1966 was still suitable for use in hemoglobin assays. These results would suggest that the current one-year expiration time used for commercial standards could be extended considerably.
