Lung function tests were performed in this study on 139 adults (mean age 36 years), as well as on 91 female persons between 16 and 18 years of age (the latter just starting on their professional careers), the lungs being healthy in each case in both groups. The findings were compared with the currently accepted reference value formulae after Quanjer et al., and Zapletal as well as further developed reference value formulae after Brändli et al., Most of the measurement data obtained by spirometry for the BGFA group of probands are between the two recommended reference values for adults with better coincidence with Brändli's predictions (exceptions being MMEF25-75 MEF 50 and MEF 25). In our studies we obtained higher values than the reference median values after Quanjer and Zapletal for IVC, FVC, FEV1 and PEF by 6-8% and 5-15%, respectively, whereas the values for adults differ from the predictions made by Brändli et al. by -4% to +5%. The flow data MMEF 75-25, MEF 50 and especially MEF 25 are set at too low levels (by 5-23%) by Zapletal's and Brändli's values. Comparatively, the values predicted by Quanjer et al. for the above mentioned flow-volume parameters (with the exception of MEF 75) are too high by 4% to 12%. There are also considerable differences in respect of the reference values for IGV to the tune of +15% in the BGFA group compared to Quanjer et al.; in the BAFAM group the values differ from those of Zapletal et al. by +17%. RV yields results in the BGFA group which are higher by 11% than according to Quanjer's formulae, whereas in the BAFAM group they are higher by 15% compared to Zapletal's predictions. In respect of Rt there are differences to the predictions by Rühle and Matthys by +16% (BGFA group) and +13% (BAFAM group), respectively. The BAFAM group differs from Zapletal's predictions by +11%. Looking at the reference limit values the overall impression is confirmed that the predictions after Quanjer et al. and mostly also those by Zapletal are too low in respect of the abovementioned lung function parameters (in the majority of cases not 5% of the examined probands, as expected, are below those levels, but only about 2%). Females, who had been underrepresented in the previous healthy proband groups, show larger deviations than males in respect of most of the parameters.(ABSTRACT TRUNCATED AT 400 WORDS)