When to perform spirometry: what it is used for and when it is truly indicated

Spirometry is one of the most important tests for assessing respiratory function. It is a simple, quick, and non-invasive test that measures the amount of air a person can inhale and exhale and the speed at which they do so.

This test is essential for diagnosing and monitoring numerous respiratory diseases, including asthma, chronic obstructive pulmonary disease (COPD), pulmonary fibrosis, and other lung diseases.

However, many patients wonder: when is spirometry really necessary?

What is spirometry and what is it used for?

Spirometry is a respiratory function test that assesses how well the lungs are working.

During the test, several key parameters are measured, including:

1. FVC (forced vital capacity): the total amount of air that can be exhaled after a maximum deep breath
2. FEV1 (forced expiratory volume in the first second): the amount of air exhaled in the first second
3. FEV1/FVC ratio, useful for identifying possible bronchial obstruction.

These parameters allow the doctor to understand whether there are any changes in respiratory function.

When to perform spirometry

Spirometry is prescribed in various clinical situations. The most common indications include the presence of respiratory symptoms, the diagnosis of certain lung diseases, and the monitoring of already known conditions.

1. In the presence of persistent respiratory symptoms

One of the most frequent reasons for performing spirometry is the presence of long-lasting respiratory symptoms, such as:

• shortness of breath (dyspnea)
• chronic cough
• wheezing
• chest tightness
• reduced exercise tolerance

These symptoms can be associated with various respiratory diseases, and spirometry is one of the first tests used to clarify the cause.

2. To diagnose bronchial asthma

Spirometry is one of the main tools for diagnosing asthma.

The test is often performed before and after the administration of a bronchodilator drug to assess whether bronchial obstruction is reversible, a typical feature of asthma.

3. In smokers or former smokers

Spirometry is particularly recommended for individuals with a history of cigarette smoking, especially after the age of 40.

Smoking is the main risk factor for COPD (chronic obstructive pulmonary disease).

In many cases, the disease can remain silent for years, and spirometry allows for the early identification of a reduction in respiratory function.

4. To monitor already diagnosed respiratory diseases

In patients with chronic respiratory diseases, spirometry is used to monitor lung function over time.

It is particularly useful for:

• asthma
• COPD
• pulmonary fibrosis
• interstitial lung diseases

Through periodic check-ups, it is possible to assess the progression of the disease and the response to therapy.

5. Before certain surgical procedures

Spirometry may also be requested before surgical procedures, especially when:

• thoracic surgery is planned
• the patient has a respiratory disease
• there are risk factors such as smoking.

In these cases, the test helps to estimate the post-operative respiratory risk.

How spirometry is performed

Spirometry is a simple test that usually takes a few minutes.

The patient breathes through a mouthpiece connected to a spirometer, following instructions from the healthcare professional.

The test involves:

1. a deep inhalation

2. a forced and prolonged exhalation

3. repeating the maneuver several times to ensure reliable results.

The test is painless and non-invasive.

Spirometry is a fundamental test for lung health and is one of the most important tools in pulmonology.

It allows for:

• early diagnosis of many respiratory diseases
• monitoring of lung function over time
• evaluation of the effectiveness of therapies.

In the presence of persistent respiratory symptoms or risk factors such as cigarette smoking, spirometry can be the first step toward a correct diagnosis.

FAQ

Is spirometry painful?

No. Spirometry is a non-invasive and painless test that generally takes a few minutes.

How long does spirometry take?

The test takes 10–15 minutes on average, although the time may vary slightly depending on the number of maneuvers required.

Is any preparation required before spirometry?

In some cases, your doctor may recommend temporarily suspending certain bronchodilator medications before the test.

Who should undergo spirometry?

Spirometry is recommended for patients with persistent respiratory symptoms, smokers or former smokers, and individuals with suspected respiratory diseases.

Prof. Luca Richeldi