TY - JOUR T1 - Prediction equations for carbon monoxide diffusing capacity of the lung (T<sub>L,CO</sub>) in healthy Bulgarian children aged 7 to 18 years JF - European Respiratory Journal JO - Eur Respir J VL - 44 IS - Suppl 58 SP - 193 AU - Stoilka Mandadzhieva AU - Blagoi Marinov AU - Stefan Kostianev Y1 - 2014/09/01 UR - http://erj.ersjournals.com/content/44/Suppl_58/193.abstract N2 - Introduction: The diagnosis of lung function impairments in childhood is highly dependent on reference values used. Previous studies for carbon monoxide diffusing capacity of the lung (TL,CO) in children have limited use because they were done by different methods and with small number of participants.Aim: The aim of this study was to derive prediction equations and normal reference values for carbon monoxide diffusing capacity of the lung (TL,CO) in healthy Bulgarian children in the age span 7-18 years.Methods: Five hundred forty nine healthy children (254 boys/295 girls) took part in the study. Study protocol included comprehensive anthropometric, spirometric and measurements for carbon monoxide diffusing capacity of the lung (TL,CO).Results: Prediction equations were calculated separately for boys and girls. There were significantly higher values for single breath TL,CO in boys compared to girls - 7.19±2.47 vs. 6.51±1.71 mmol.min-1kPa-1 (p‹0.001). Alveolar volume (VA) in both genders shows similar values. TL,CO and VA showed close correlations with height (r2 between 0.82 and 0.90). With increasing height all children presented a faster increase in TL,CO than in VA. Height (Ht) explained the maximum variance for TL,CO parameters and the best-fit regression equation relating functional parameters and body height was the exponential function Y=b0ˆ(eˆˆ(b1ˆht)).Conclusions: The developed prediction equations can be used in clinical practice. Compared with reference equations based on other populations, regional reference values are biologically more suitable for the interpretation of spirometric data. ER -