Lung diffusion test

The lung diffusion test is a diagnostic method that evaluates how effectively oxygen from inhaled air passes into the bloodstream and binds to the hemoglobin in red blood cells. This examination is performed not only in the case of various lung diseases but also in the context of other conditions such as vasculitis, obesity, pulmonary embolism, and others.

How is the examination performed?

During the lung diffusion test, the patient is asked to inhale a special gas mixture. After inhaling the mixture, the patient must hold their breath for 10 seconds, then exhale the gas mixture. This maneuver is repeated several times.

While performing the breathing maneuvers, the patient may experience temporary dizziness, fatigue, or an increased heart rate. These sensations occur due to the deep and rapid breathing required during the examination.

Indications for lung diffusion testing

The lung diffusion capacity test is utilized both for diagnostic purposes and for monitoring treatment efficacy in patients with various respiratory and systemic conditions, including:

• Chronic Obstructive Pulmonary Disease (COPD);
• Pulmonary fibrosis and other interstitial lung diseases;
• Asthma and other obstructive airway disorders;
• Pulmonary hypertension and related vascular pathologies;
• Smoking-induced pulmonary damage;
• Vasculitis with potential pulmonary vascular involvement;
• Overweight and obesity-related respiratory impairment.

This test plays a critical role in the ongoing assessment of disease progression and therapeutic response.

When are pulmonary function tests not performed?

Pulmonary function tests cannot be performed if, within the last 4 weeks, there has been:

• Chest or abdominal surgery;
• Pneumothorax;
• Myocardial infarction;
• Infection of the nose, sinuses, or ears;
• Surgery involving the nose, sinuses, or ears;
• Eye surgery;
• Brain surgery;
• Concussion (traumatic brain injury).

Is the patient at increased health risk:

• Cerebral, aortic, or other vascular aneurysm;
• History of loss of consciousness, severe coughing fits, or forceful exhalation;
• Recent or current hemoptysis (coughing up blood);
• Severe arterial hypertension;
• Uncontrolled pulmonary hypertension.

How to prepare for the test?

You should come to the lung gas diffusion test with a recent blood test measuring hemoglobin (Hgb) levels to ensure accurate and reliable results.

Before the test:

• Refrain from smoking and using intoxicating or narcotic substances for at least 24 hours prior to the test;
• Avoid heavy meals 2–3 hours before the examination;
• Avoid intense physical activity before the test;
• Arrive for the test wearing comfortable, loose-fitting clothing, especially on the upper body, to facilitate deep and rapid breathing maneuvers;
• Consult your physician regarding any medications that may affect the test results.

​​Before the examination, please inform the medical staff if you have arterial hypotension, cardiac arrhythmias, decompensated heart failure, or unstable angina; if you have recently experienced a pulmonary embolism; if you are currently suffering from tuberculosis or another respiratory infection and/or are receiving treatment for such conditions; if you currently have oral mucosal lesions or bleeding from the oral cavity; or if you are pregnant.

Our center offers precise and professional pulmonary diffusion testing using advanced equipment and ensures an individualized approach for every patient.