Tests for Diagnosing Breathing Problems

There are a number of medical conditions that can cause or worsen breathing problems; COPD being one of the most common. If you’re experiencing respiratory symptoms such as shortness of breath, increased mucus production, coughing, chest tightness or wheezing, you should make an appointment with your health care provider as soon as possible for a complete history and physical.

During your medical appointment, your doctor will examine you and ask you questions about your health history. She will also ask you questions about your smoking history and if you’ve been exposed to any other types of environmental irritants. Once your doctor has finished examining you, she may order any of the following tests to help her establish an accurate diagnosis:

Pulse oximetryA pulse oximeter is a non-invasive device that measures your oxygen saturation levels. Normal oxygen saturation levels run between 95 to 100 percent. An oxygen saturation level of 88% or below at rest, or for at least five minutes during sleep, constitutes a need for supplemental oxygen, which may relieve your breathing problems.

Arterial blood gas (ABG) studies – Results obtained from arterial blood gas studies are often used to diagnose breathing problems and the need for supplemental oxygen. ABGs involve drawing blood from an artery, usually in your wrist. In general, a blood oxygen level of 55 mg Hg or lower means that you would benefit from oxygen therapy.

Complete blood count (CBC) – The CBC is a routine test that gives your doctor a detailed description of the number of white and red blood cells that are circulating in your blood. Although mostly used for assessing general health, abnormal results on a CBC can reveal conditions such as infection or anemia, which will help your doctor better understand the reason for your symptoms.

Chest X-Ray – A chest x-ray is usually one of the first things your doctor will order if you’re experiencing difficulty breathing. Although a chest x-ray alone does not definitively diagnose COPD, it can help corroborate one or point your doctor to other illnesses that may be responsible for your breathing problems, such as pneumonia or pulmonary tuberculosis.

Computed Tomography (CT) Scan – CT scans are generally not used to diagnose lung disease; however, if your doctor suspects a lung infection like pneumonia, or you’re currently being treated for an infection and your symptoms are worsening, she may order a CT scan of the chest. This noninvasive imaging study helps your doctor clearly visualize the blood vessels within your lungs and detect any abnormalities.

Pulmonary Function Tests (PFTs) – PFTs provide your doctor with a complete evaluation of your respiratory system. To date, they are the gold standard in identifying, and determining the severity of, lung disease. There are three types of pulmonary function tests used in the diagnosis of COPD and other lung disorders:

  • Spirometry – A spirometry test measures the amount of air coming in and out of your lungs; it is the most common of all pulmonary function tests. The test – which can easily be performed in your doctor’s office – uses a handheld device called a spirometer, which measures your breathing, then records and analyzes your results. Once the results are analyzed, your doctor will interpret them and explain the results to you.
  • Lung diffusion tests – Under normal circumstances, when oxygen is inhaled, it travels through the lungs to your alveoli where it is then diffused into your bloodstream. At the same time carbon dioxide diffuses from your blood back through your alveoli and out your lungs to be exhaled. This process is known as gas exchange. Lung disease causes the process of gas exchange to be impaired. Lung diffusion tests measure how well oxygen moves from your lungs into your bloodstream.
  • Body plethysmography – During the breathing process, people with COPD are unable to expel all their inspired air. Over time, residual air left in the lungs contributes to worsening breathing problems. Body plethysmography tells your doctor how much air is present in your lungs when you take a deep breath and how much air is left in your lungs after you exhale.


Tests for diagnosing breathing problems are generally non-invasive and pain free. If you, or anyone you know is experiencing minor breathing problems, make an appointment with your health care provider as soon as possible. Severe breathing problems, such as worsening shortness of breath that is unrelieved by rest, is a true medical emergency and warrants prompt medical attention.


Author: Deborah Leader RN, BSN, PHN


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