What is spirometry?

Spirometry is a diagnostic test used to assess lung function and diagnose respiratory disease. In this test, a person breathes into a device called a spirometer.

Who performs spirometry?

Pulmonologists (chest physicians), respiratory therapists, technicians, and trained nurses conduct spirometry test.

Spirometry can be performed at a clinic, hospital, or specialized pulmonary function testing lab. It is carried out using a device called a spirometer, which is a small machine attached by a cable to a mouthpiece.

Why is spirometry done?

Spirometry is often performed in individuals with respiratory symptoms, such as wheezing, shortness of breath, chest tightness, or a persistent cough. This test helps diagnose conditions like asthma and chronic obstructive pulmonary disease (COPD) or assess lung function before surgery.

It can also be used to monitor the progress of chronic lung diseases, such as COPD, asthma, or pulmonary fibrosis, and evaluate the effectiveness of medications or inhalers.

How is the spirometry test performed?

Preparation before test

On the day of the spirometry test, the doctor may advise the patient to refrain from using certain inhalers or medications. It is recommended to wear loose clothing and avoid heavy meals before the test.

The spirometry test itself is not painful. A technician will guide the patient through the process. The test will be repeated multiple times to ensure accurate results.

During the test, remember the following:

  • The patient is advised to take regular medications as prescribed unless instructed otherwise by the doctor.
  • Avoid smoking for at least six hours prior to the test.
  • The patient is advised to use a short-acting inhaler as needed and asked to refrain from using it for six to eight hours before the test.
  • The doctor may provide specific instructions regarding medications or other preparations for the test.

During the spirometry test, the patient is usually seated in an upright position in a chair or on an examination table. A nose clip will be placed on the patient’s nose to ensure that all exhaled air goes through the mouthpiece of the spirometer. The patient will be instructed to place the lips around the mouthpiece of the spirometer tightly. The test involves taking a deep breath in and then blowing out forcefully and rapidly. The test will be repeated at least three times to obtain the best measurements.

In some cases, the technician may administer medication to help open up airways. After taking the medication, the test will be repeated to assess any improvements in breathing.

The entire testing process typically lasts about 30 to 45 minutes.

What do the results mean?

A spirometer measures the amount of air the patient can forcefully exhale in one second and the total volume of air can exhale in a single breath.

These measurements will be compared to normal values for someone of the patient’s age, height, and sex. This comparison helps determine if the patient’s lungs are functioning properly. Normal values are determined based on age, height, and gender. If any of the test results fall outside the normal range, it may indicate a lung problem. However, it is important to note that sometimes a person with healthy lungs may have an abnormal test result.

The referring doctor will explain the meaning of the test results and provide appropriate guidance. Depending on the results, they may prescribe inhalers or medications to help improve lung function. In some cases, the test may be repeated during future visits to monitor changes in lung function over time.

Are there any risks or discomfort involved?

Spirometry is a safe and non-invasive procedure. Some people may feel lightheaded or dizzy after blowing forcefully, but these symptoms are temporary and usually resolve quickly.


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