TY - JOUR T1 - Exhaled carbon monoxide is not elevated in patients with asthma or cystic fibrosis JF - European Respiratory Journal JO - Eur Respir J SP - 197 LP - 198 DO - 10.1183/09031936.02.00078702a VL - 21 IS - 1 AU - W. Zetterquist AU - J.O.N. Lundberg AU - K. Alving Y1 - 2003/01/01 UR - http://erj.ersjournals.com/content/21/1/197.2.abstract N2 - From the authors: We appreciate the interest P. Paredi and colleagues have shown in our article. In their letter, they describe some differences in the methodologies used and suggest that these differences may explain why our results on exhaled carbon monoxide (CO) in asthma and cystic fibrosis 1 contrast with their previous findings. We agree that it is preferable to use standardised methods, but there is as yet no consensus on standardised methods for exhaled CO measurements.With regard to possible contamination with nasal CO, we did have our patients exhale against a resistance using … ER -