Age and Bronchial Hyperresponsiveness Are Associated with Failure to Perform the Single Breath N 2 Test in a Rural Female Population D. Teculescu, 1 A. B. Bohadana, 1 S. E. Megherbi, 1 E. Costantino, 2 and Q. T. Pham 1 1 Institut National de la Sante ´ et de la Recherche Me ´dicale (I.N.S.E.R.M.), Unite ´ 420, B.P. 184, 54505 Vandœuvre-Le `s-Nancy Cedex, France, and 2 II Divisione Pneumologia, Policlinica Bari, Bari, Italy Abstract. Because some authors have reported high rates of failure in performing the single breath N 2 (SBN 2 ) test in rural areas, the present study aimed at evaluating its acceptability in a female population, unfamiliar with lung function testing, in a rural area of northeastern France. Two hundred ninety-eight women from a rural area volunteered for a preventive medicine examination (91.6% of those invited); four of them were excluded for clinical reasons, and six (2%) were unable to perform spirometry. The protocol included completion of a questionnaire, spirom- etry with a bronchial reactivity test, skin prick test, and the SBN 2 test utilizing a computerized assembly. Although failures caused by the apparatus were few (n  7, 2.4%) 96 of 281 women (34.1%) were unable to produce two valid SBN 2 tests in a series of six attempts. Compared with the group who succeeded in the test (n  185), women who failed were older and had a higher prevalence of bronchial hyperresponsiveness. Logistic regression confirmed the independent association of these two variables with an inability to perform. We conclude that in a female population completely unfamiliar with lung function testing the SBN 2 test has a high rate of failure associated with higher age and the presence of bronchial hyperre- sponsiveness. Key words: Single breath N 2 test—Acceptability—Field survey. Introduction The single breath nitrogen washout (SBN 2 ) test was originally used in clinical physi- ology laboratories; it became of interest for epidemiologists when it was shown that This paper was presented in abstract form at the 1998 Annual Meeting of the American Thoracic Society, April 26, Chicago, IL. Offprint requests to: D. Teculescu Lung (1999) 177:151–159 © Springer-Verlag New York Inc. 1999