Healthcare professionals use X-rays to check the airways and lungs. This can help them diagnose bronchitis or rule out other lung conditions that also cause a persistent cough.

Bronchitis occurs when an infection causes inflammation in the airways that bring air to the lungs. It causes a phlegmy cough that may last for several weeks. Often, bronchitis resolves without treatment.

However, bronchitis has similar symptoms to other, more severe health problems, such as pneumonia or asthma, that healthcare professionals may need to rule out during diagnosis.

This article explains how healthcare professionals use X-rays to confirm a bronchitis diagnosis and recommend next steps.

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Healthcare professionals may use a chest X-ray in order to view images of the lungs and bronchial tubes, the airways through which air reaches the lungs.

They typically do this to rule out pneumonia rather than directly identify signs of bronchitis. X-rays create an image of the body’s internal structures by passing invisible radiation through the body.

The X-ray imaging for someone with bronchitis will usually appear typical. Bronchitis does not generally require further investigation if vital signs are within a normal range and the X-ray does not show significant lung changes.

Pneumonia, however, may show a substance in the lungs known as an infiltrate on an X-ray. This may be blood, protein, or pus that suggests lung rather than airway infection.

For people with acute or short-term bronchitis, a healthcare professional will typically not need to request any other imaging once an X-ray has ruled out other conditions.

However, a healthcare professional may request a CT scan, which is more sensitive than an X-ray and produces more detailed images. This may be useful if an X-ray does not show abnormalities but the healthcare professional still suspects infection due to other symptoms.

A high-resolution CT scan may find pneumonia up to 5 days earlier than an X-ray.

X-rays can support bronchitis diagnosis by excluding other conditions. However, blood tests, lung function tests, and others can help to diagnose the cause of bronchitis, assess how the lungs are working, and guide treatment.

People may need to seek a diagnosis if the following apply:

  • They are coughing up mucus.
  • Their chest hurts when they cough.
  • They find it harder to breathe than usual.
  • They have a sore throat, a runny nose, and a fever.

Complete blood count

A healthcare professional can request a blood test to help identify an infection’s presence. This includes the volume of white blood cells, which would increase in response to an infection.

Sputum culture

A sputum culture checks for bacteria, fungi, and other substances in phlegm that may be causing the infection.

One test, the polymerase-chain-reaction (PCR) test, can detect multiple bacteria that can cause bronchitis. This may not happen for every individual. However, healthcare professionals may carry out rapid flu testing, pandemic virus testing, and testing for bacterial infections.

Pulmonary function test

A pulmonary or lung function test shows how well the lungs work by measuring the volume of air they can hold and how much a person can forcefully breathe out. Spirometry is the particular test that healthcare professionals use for airway diseases, as these can reduce how effective the lungs are at holding air.

Acute bronchitis may cause lung function changes. Lung function tests such as spirometry can show if the airways are spasming too easily, also known as hyperresponsiveness. This can reveal how severe a presentation of bronchitis is.

Pulse oximetry

Pulse oximetry measures the amount of oxygen in the blood, also known as blood oxygen saturation. Acute bronchitis may reduce this. Healthcare professionals can use pulse oximetry to determine the severity of bronchitis.

Most people with bronchitis do not need medical treatment. They develop bronchitis due to a viral infection, and treatment involves home remedies to soothe symptoms. These may include:

  • using over-the-counter cough relief medicines containing dextromethorphan or guaifenesin
  • drinking hot water or tea with honey
  • sucking on throat lozenges
  • having a humidifier nearby
  • using an albuterol inhaler, a symptom relief medication, if a healthcare professional prescribes it

If a healthcare professional finds bacteria in the sputum culture, they may prescribe antibiotics to treat the infection. However, antibiotics are not a suitable treatment for viral bronchitis.

Doctors use X-ray imaging to rule out pneumonia, which causes symptoms similar to bronchitis but requires more intensive treatment. A doctor may request a computerized tomography (CT) scan if an X-ray shows up normal but they still suspect infection.

However, for most people, no further imaging is necessary if an X-ray rules out abnormal airway changes. Blood tests, sputum cultures, lung function testing, and pulse oximetry are vital to determining the severity and cause of bronchitis.