Early diagnosis and timely intervention in COPD can significantly slow down or halt the progression of the disease. The diagnostic process begins with a detailed evaluation of the patient's symptoms and complaints. This is followed by the use of pulmonary function tests (PFTs) and imaging methods such as chest X-rays. Respiratory capacity is measured by comparing it to expected normal values, taking into account factors such as the patient's age, gender, and body weight. Pulmonary function tests not only allow for the diagnosis of COPD but also for the determination of the disease's severity. Blood oxygen level measurements, specific blood tests, and exercise tests are among other important supplementary diagnostic procedures.