Abstract
The spectrophotometric method of Commins and Lawther (1965) for estimating carbon monoxide in small samples of blood (0.03 cm3) has been adapted for use in industrial hygiene with particular reference to certain problem areas. Blood specimens are collected and sealed into short lengths of heparinized capillary tubing. Once sealed, the specimens will keep for several days allowing for delays such as mailing prior to analysis. The accuracy and limitations of the method are discussed.