The breath test is recommended in the diagnosis of certain respiratory conditions. This is an examination which takes place using a machine and under the supervision of a healthcare professional. The breath test makes it possible to detect pathologies such as asthma or chronic obstructive pulmonary disease (COPD).
1. What is the breath test?
The breath test, generally called spirometry, is part of a set of tests called pulmonary function tests (PFA). As the Lyon University Hospital specifies on its website, “spirometry allowsstudy ventilatory flow rates and mobilizable volumes “. The breath test makes it possible to collect two important data:
- The maximum exhaled volume in one second (FEV), which is the maximum volume that the patient can exhale in one second.
- Vital capacity, which is the total volume mobilized after maximum inspiration and expiration.
- The median maximum expiratory flow (MEF), which corresponds to the maximum flow of exhaled air during a forced expiration.
2. When to take a breath test?
The breath test, or spirometry, is recommended in many cases. It is initially prescribed when a patient presents the following symptoms:
- breathing difficulties;
- wheezing;
- a persistent cough;
- frequent lung infections.
The breath test may also be recommended when there is risk factors, such as smoking, but also the practice of certain professions exposing to toxic substances. The construction trades or in the steel sector are, for example, part of this. In addition, the breath test can be recommended for patients with lung disease, in order to monitor the evolution of their state of health. Finally, high-level or elderly athletes can take a breath test in order to better understand their lung capacities. In all cases, it is recommended to consult a healthcare professional quickly in case of doubt, in order to benefit from rapid and personalized support if necessary.
3. At what age is the breath test recommended?
Spirometry can be performed at any age, if the healthcare professional deems this test necessary. “An experienced person can perform spirometry on children from 3 to 4 years old. For less experienced testers, it is recommended not to do spirometry before the age of 7-8 years.
4. Breath test: how does it work?
The breath test is an examination that generally lasts between 15 and 30 minutes, and is completely painless. It is advisable to eat light, not to smoke, not to drink alcohol and not to exercise physically in the hours before spirometry. This test is carried out with a device called a spirometer. This device is connected to a computer. The test is supervised by a healthcare professional. Generally, the exam proceeds as follows. After answering a quick questionnaire to draw up their profile, the patient positions themselves in front of the spirometer, sitting or standing. He takes a deep breath and places his mouth on the tip of the spirometer. He blows as hard and as long as possible into the machine, to expel all the air from his lungs. This test is repeated several times to refine the measurements. The test results will then be presented in the form of a curve and expressed as percentages, compared to the normal values of a person of the same age, sex and build.
5. What diseases can be diagnosed with a breath test?
The breath test can help confirm the diagnosis of several diseases. This can for example be the case with:
- Asthma: spirometry measures the quantity of air that the patient can inhale and exhale, which makes it possible to detect this common chronic inflammatory disease, or to assess its level of severity.
- Chronic obstructive pulmonary disease (COPD): this chronic lung disease is characterized by airway obstructionthe breath test is therefore a reference examination for its diagnosis.
- Pulmonary fibrosis: the breath test helps to confirm the presence of this disease, which is characterized by scarring and stiffness of the lung tissues, and above all to assess its severity.
- Emphysema: this progressive disease, which is one of the complications of COPD, gradually destroys the pulmonary alveoli; the breath test therefore makes it possible to confirm that the patient’s respiratory capacity is reduced.
- Respiratory allergies: spirometry is one of the tests indicated to evaluate allergic asthma.
Sources
Lyon University Hospital, Spirometry.info, Inserm, CHU network
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