ABSTRACT. Objective. The aim of this study was to investigate the validity of office spirometry in primary care pediatric practices.Methods. Ten primary care pediatricians undertook a spirometry training program that was led by 2 pediatric pulmonologists from the Pediatric Department of the University of Padova. After the pediatricians' training, children with asthma or persistent cough underwent a spirometric test in the pediatrician's office and at a pulmonary function (PF) laboratory, in the same day in random order. Both spirometric tests were performed with a portable turbine flow sensor spirometer. We assessed the quality of the spirometric tests and compared a range of PF parameters obtained in the pediatricians' offices and in the PF laboratory according to the Bland and Altman method.Results. A total of 109 children (mean age: 10.4 years; range: 6 -15) were included in the study. Eighty-five (78%) of the spirometric tests that were performed in the pediatricians' offices met all of the acceptability and reproducibility criteria. The 24 unacceptable test results were attributable largely to a slow start and failure to satisfy end-of-test criteria. Only the 85 acceptable spirometric tests were considered for analysis. The agreement between the spirometric tests that were performed in the pediatrician's office and in the PF laboratory was good for the key parameters (forced vital capacity, forced expiratory volume in 1 second, and forced expiratory flow between 25% and 75%). The repeatability coefficient was 0.26 L for forced expiratory volume in 1 second (83 of 85 values fall within this range), 0.30 L for forced vital capacity (81 values fall within this range), and 0.58 L/s for forced expiratory flow between 25% and 75% (82 values fall within this range). In 79% of cases, the primary care pediatricians interpreted the spirometric tests correctly.Conclusions. It seems justifiable to perform spirometry in pediatric primary care, but an integrated approach involving both the primary care pediatrician and certified pediatric respiratory medicine centers is recommended because effective training and quality assurance are vital prerequisites for successful spirometry. Pediatrics 2005;116:e792-e797. URL: www.pediatrics.org/cgi/ doi/10.1542/peds.2005-0487; office spirometry, primary care pediatrics, asthma, children.ABBREVIATIONS. PF, pulmonary function; FEV 1 , forced expiratory volume in 1 second; ATS, American Thoracic Society; FVC, forced vital capacity; FET, forced expiratory time; FEF , forced expiratory flow between 25% and 75% of expired FVC; ICC, intraclass correlation coefficient; GP, general practitioner. P ulmonary function (PF) tests are useful in both the diagnosis and the monitoring of lung disease. The international guidelines for asthma management have endorsed the use of objective lung function measures for assigning a severity rating to patients with asthma and guide asthma therapy. 1 Although children's and their parents' reporting of asthma symptoms is important in staging and managing ped...