Carboxyhemoglobin Levels in American Blood Donors

A national survey was conducted in 1969-1972 for the purpose of determining the range of carboxyhemoglobin (COHb) levels in various segments of the American population. Venous blood samples for COHb analysis were obtained from 29,000 blood donors living in urban, suburban, and rural communities across the United States. For comparative purposes, COHb measurements were made on samples obtained from 11 volunteers breathing air free of carbon monoxide (CO) or air with known concentrations of CO. The mean COHb saturation of four adults breathing CO-free air was 0.45%. Fortyfive percent of all the nonsmoking blood donors tested had COHb saturations of more than 1.5% This indicated that exposure to CO in excess of that permitted by the Air Quality Standards was widespread and occurring regularly. Tobacco smoking was the single most important factor responsible for the highest COHb saturations observed. The other chief factors influencing the COHb saturation were the geographical location of the individual, occupation, and the existing meteorological conditions. (JAMA229:1187-1195, 1974)