Gil-Guillén et al. BMC Public Health 2011, 11:413 http://www.biomedcentral.com/1471-2458/11/413 Page 4 of 6 Figure 1 Flow diagram of the FUMEPOC study. petition sheet of spirometry in the hospital and the result of screening will be not given to the patient until both tests have been performed. So a final report on the results of the two tests will be sent to patients. Prior to the start of the study reproducibility of the test must be assessed. A poorly reproducible test may affect the validity of the results. In our study the screen- ing instrument COPD-6, is a perfectly reproducible test in patients with different clinical and pathological states. Regarding “gold standard” selection, Conventional Spirometry is the gold standard for diagnosing the dis- ease and monitoring its progression as it is non-invasive, standardised, reproducible, and objective. Functional diagnosis of COPD is important for identifying and quantifying airflow limitation, reversibility, disease sever- ity and exacerbations. Functional diagnosis is also important for long-term therapeutic monitoring and for establishing the need for pulmonary rehabilitation [14]. Spirometry ought to be used in primary care as a screening tool for the early detection of COPD in all patients > 45 years of age who are currently smoking, as well as those with respiratory symptoms [15]. But Spirometry is difficult to use widely in PC setting. To implement screening tools in primary care it needs to be trough a simpler, cheaper test because of the pri- mary care clinic conditions [16].