Abstract
Pulmonary function tests are essential for the diagnosis and management of chronic obstructive pulmonary disease (COPD). It is important to detect the presence of airflow limitation by spirometry at medical examination for screening of COPD. Because spirometry is affected by gender, age, height, and ethnicity, measurement results must be compared to reference values adjusted for these factors. Japan Respiratory Society (JRS) published new spirometric reference values and lower limit of normal (LLN) for Japanese adults in 2014. The new reference values for FEV1/FVC are smaller than previous values in both genders. The LLN of the FEV1/FVC for females is larger than previous values. The presence of a post-bronchodilator FEV1/FVC < 0.7 confirms the presence of persistent airflow limitation and the diagnosis of COPD. Fixed lower limit of 0.7 crossed with the LLN at about 60 years in males and at about 70 years in females. The use of a fixed ratio of FEV1/FVC<0.7 to define COPD leads to an underdiagnosis apart from the elderly.
