Verification of the new 'all ages' spirometric reference values for use in young Polish children of Caucasian origin

Z-scores and percent of predicted values were calculated for FEV1, FVC and FEV1/FVC using both sets; additionally z-score and percent predicted was also calculated for FEV0.75/FVC using Stanojevic's equation. The distribution of all calculated z-scores was normal. For FEV1/FVC mean ± SD of z-score was 0.01 ± 0.80 using GLI2012 and −0.15 ± 0.79 using Stanojevic's set. Mean value of percent predicted values using GLI2012 was 100.2 ± 5.5% for FEV1/FVC, 107.4 ± 9.4% for FEV1 and 106.6 ± 10.1% for FVC. Our results confirm applicability of the new sets of reference values in young Caucasian children from Poland and point out the potential diagnostic value of FEV0.75/FVC.