[The different ways of expressing the results of the monoxide test in steady state: discussion and proposition of reference values for epidemiological studies (author's transl)].

The results of the steady state carbon monoxide test can be expressed quantitatively as the amount of CO absorbed by the lung per minute and per 1 mm Hg pressure difference (TCO; ml/min/mm Hg) or as the ratios between partial pressures of CO (FICO, FECO, FACO), fractional untake coefficient (Formula: see text), From measurements taken in 141 non-smokers (mean age 47.43 +/- 6.4 years), 60 ex smokers (mean age 45.73 +/- 5.29 years) and 322 smokers (mean age 46.65 +/- 5.5 years), TCO and fractional uptakes were calculated and discussed. Considering the fact that mean TCO had a larger standard deviation that mean FUCO and that TCO had a non-Gaussian distribution, the authors chose to express the results of the test in fractional uptakes. Equations are proposed to calculated fractional uptakes.