Introduction Management of asthma or COPD patients in primary care can be difficult. In order to assist GPs in the northern part of the Netherlands the Asthma/COPD service of LabNoord was developed. The service assesses patients based on questionnaire data and spirometry using the online advice of pulmonologists. One of the advices can be to refer the patient to secondary care. In this study the additional benefits of a one-time referral to secondary care in gaining a correct diagnosis and change in asthma control or COPD health status are assessed. Methods A cross-sectional study was performed including patients from the area around Delfzijl that visited the service in 2008. Data from the Asthma/COPD service, medical files from the pulmonology department in Delfzijl and questionnaires sent to all patients approximately one year after visiting the service were obtained. Results Patients advised to be referred to secondary care had an uncertain diagnosis or had more prominent symptoms. About half of these patients visited the pulmonologist. A confident diagnosis could be established in 85,7% of the referred patients. Patients without the advice for referral had better asthma control at baseline. Patients that did and did not visit the pulmonologist both showed significant improvement in asthma control after one year. No statistical significant differences in COPD health status were found between patients with and without the advice for referral at baseline and after one year. Conclusions The one-time referral adds to gaining a confident diagnosis. The role of the Asthma/COPD service in improvement of asthma control and COPD health status is encouraging but due to limited numbers in this study needs to be further investigated.