From the Guidelines
Pulmonary function tests (PFTs) in patients with asthma should be repeated at least every 1-2 years, with more frequent testing for patients with not well-controlled asthma, as recommended by the expert panel report 3 (epr-3) guidelines 1. The frequency of PFTs in asthma patients depends on various factors, including asthma severity, control level, and treatment changes.
- For stable patients with well-controlled asthma, PFTs should be performed every 1-2 years, as stated in the guidelines 1.
- However, for patients with not well-controlled asthma, more frequent testing is recommended, with intervals of 3-6 months, to monitor disease progression and treatment effectiveness 1.
- Spirometry is the most common PFT used for asthma monitoring, measuring FEV1 (forced expiratory volume in one second) and FVC (forced vital capacity), with the FEV1/FVC ratio being particularly important for evaluating airflow obstruction in asthma patients 1.
- The 2020 focused updates to the asthma management guidelines also suggest that FENO testing may be useful in monitoring asthma, particularly in individuals with uncontrolled persistent asthma, but it should be used in conjunction with other clinical data and not as a substitute for other measures of asthma control 1.
- Ultimately, the frequency of PFTs should be individualized based on asthma severity, control level, and treatment changes, with the goal of optimizing asthma management and improving patient outcomes.
From the Research
Pulmonary Function Tests (PFTs) in Asthma
- PFTs are essential in the management of asthma, as they help assess the severity of airway obstruction and monitor the effectiveness of treatment 2.
- The frequency of repeating PFTs in patients with asthma is not strictly defined, but it is recommended to repeat them as needed to assess treatment response and disease progression.
Factors Influencing PFT Frequency
- Patient age: younger patients (7-9 years old) and older patients (70 years or older) are less likely to receive PFTs than younger adults 3.
- Socioeconomic status: patients from lower-income neighborhoods are less likely to receive PFTs than those from higher-income neighborhoods 3.
- Specialist care: patients seeing a medical specialist are more likely to receive PFTs than those seeing only a general practitioner 3.
Relationship between PFTs and Asthma Control
- PFTs, such as spirometry and peak expiratory flow (PEF) indices, are weakly correlated with asthma control test (ACT) scores 4.
- PFTs should be used in combination with ACT scores and/or exhaled nitric oxide measurements to assess asthma control 4.
Types of PFTs
- Baseline spirometry: provides a "snapshot" of asthma severity and airways obstruction 5.
- Post-bronchodilator FEV1: measures the best lung function that can be achieved by bronchodilator therapy on the day of the visit 5.
- Airway responsiveness (bronchial challenge): measures the degree to which an individual withstands nonspecific stimuli that trigger asthmatic attacks 5.
- Ambulatory monitoring: provides multiple measurements of the degree of obstruction for days to weeks in the patient's natural setting 5.