[Value and reproducibility of TLCO, TMCO and Vc in healthy subjects (author's transl)].

Transfer factor (TLCO) and its components (TMCO and Vc) have been measured in 47 healthy subjects. The regressions with respect to age and body surface were close to those found in the literature. The reproducibility of these indices has been investigated in a sub-group of 5 subjects, examined at two days intervals, for 24 to 42 days. For TLCO measured with a 16% O2 mixture, the reproducibility was good (coefficient of variation of 5%). For Vc and TMCO, the dispersion was more important and varied among the subjects. The lack of reproducibility appeared to be due, among other factors, to reading errors on the variables, and more frequently FACO. Four among these 5 subjects were asked to keep alveolar pressure close to atmospheric during the apnea; the coefficient of variation decreased from 23.5 to 7.5% for Vc and from 25.9 to 12.4% for TMCO.