If you have a persistent cough, you may consider having an X-ray. X-ray scans can help identify what might be causing an ongoing cough and help you get the proper treatment. Our guide explains what shows up on a chest X-ray, what conditions it can diagnose, and what you can expect from your chest X-ray results.

Chest X-ray: What to expect

If you've been dealing with a nagging cough that won't go away, your doctor may recommend getting a chest X-ray. A persistent cough that lasts for several weeks can be a sign of an underlying condition, and a chest X-ray can help detect any abnormalities in your lungs or surrounding areas.

What is a chest X-ray?

A chest X-ray is a non-intrusive and painless imaging test that uses small amounts of radiation to create images of the inside of your chest, including the heart, lungs, blood vessels and bones within the chest.

How is a chest X-ray done?

You don’t need to do anything special before an X-ray; you can eat and drink normally before the procedure. Your technician will ask you to remove any jewellery. They may give you a hospital gown to wear, or if you’re wearing loose, comfortable clothing, this may be fine to keep on. They will ask you to stand upright against a flat surface called a photographic plate, which may feel a bit cold!

You'll need to hold your breath for a few seconds while the X-ray machine captures the frontal and lateral views by sending X-ray beams through your chest onto the detector. It's important to remain completely still during the short exposure to prevent the images from blurring.

The entire process is very quick, taking just a few minutes once you’re in position. For a standard two-view chest X-ray, one image is taken from the front and another from the side angle. Sometimes, your radiologist may take extra views from other angles.

What does a chest X-ray show?

A chest X-ray allows your doctor to take a closer look at the lungs, heart, bones, and surrounding soft tissues for any abnormalities like infections, tumours, injuries, or other diseases.

On a healthy lung X-ray, the lungs should appear black or dark grey, which shows they are filled with air. The fields within the lungs should be clearly visible, and there should be no dark masses. The diaphragm (the muscles that separate the lungs from the abdomen) should be smooth and curved. There should be no signs of excess air or fluid in the chest cavity around the lungs.

The results of a chest X-ray that indicates abnormalities, disease, or infection may show:

areas of density or shadow that appear whiter or hazier than the rest of the lungs
cavities or areas with fluid buildup or air around the lungs
abnormalities in the shape of the lungs
problems with the shape and positioning of the diaphragm
foreign objects that have been inhaled into the lungs

When to get a chest X-ray for a cough

You should book a chest X-ray if you have a cough and:

it’s lasted for three weeks or more
you experience wheezing or shortness of breath
you’re coughing up yellowish-green phlegm
you have a weakened immune system

While a cough is often just a temporary annoyance caused by a cold or mild respiratory infection, it could also indicate something more serious like pneumonia, bronchitis, or even lung cancer in some cases, although this is rare.

You should seek urgent help from your GP or NHS 111 if:

your cough is very bad or rapidly getting worse
you feel very unwell
you’re coughing up blood
you have chest or shoulder pain
the sides of your neck are swollen and painful
you’re having difficulty breathing

What can a chest X-ray diagnose?

What does a chest X-ray show for cough?

An X-ray can show if a persistent cough is caused by something unusual in the lungs, like a growth or a buildup of fluid, which would appear as hazy, cloudy or bright spots on the image.

What does a chest X-ray show for shortness of breath?

It can detect problems like excess fluid in the lungs, a collapsed lung, or an enlarged heart, which may be visible as cloudy areas, shifted organ positions, or an abnormally large heart shape - all of which can make breathing difficult.

What does a chest X-ray show for chest infection?

Chest infections like pneumonia or bronchitis often appear on an X-ray for chest infection as hazy or bright patches in the lung areas, indicating inflammation or fluid caused by the infection.

What does a chest X-ray show for bronchitis?

While a bronchitis chest X-ray isn’t always conclusive, it can show signs of inflammation or lung infection.

What does a chest X-ray show for pneumonia?

Pneumonia frequently appears on an X-ray as dense, cloudy areas in the lungs, representing pus or fluid buildup in the air spaces caused by the lung infection.

What does a chest X-ray show for long COVID?

For long COVID cases, an X-ray may reveal haziness or scarring in the lung areas, which could explain persistent breathing issues after having COVID-19.

Can a chest X-ray show heart blockage or heart problems?

Yes, a chest X-ray can sometimes show signs of heart problems or blocked arteries, although it’s not the gold-standard imaging technique doctors use to examine the heart and blood vessels.

A chest X-ray may reveal:

An enlarged heart: If the heart looks bigger than usual on the X-ray image, it could mean conditions like heart failure or fluid buildup around the heart.
Calcium buildup in major arteries: Hardened or calcified areas in the major artery from the heart (the aorta) can sometimes be seen, which may be a sign of blocked or narrowed arteries.
Fluid in the lungs: If the lungs appear hazy or cloudy, it could be a sign of fluid buildup caused by a weakened heart's inability to pump efficiently (heart failure).
Heart shifted out of place: If the heart seems pushed out of its normal position, it may be due to a bulging area (aneurysm) in the aorta pushing on the heart.

A chest X-ray cannot diagnose a heart attack or blocked heart arteries or check how well the heart is pumping and blood is flowing. In these cases, a doctor will recommend more advanced imaging techniques, such as an echocardiogram or CT scan. However, an abnormal finding on a chest X-ray can help your doctor identify whether you need further tests or scans.

Worried about chest X-ray results?

Feeling anxious or worried while waiting for your chest X-ray results is normal. However, try not to let your concerns get the better of you. Remember that diagnosing what’s causing your cough is vital to accessing the proper treatment and care plan.

When you book your chest X-ray with Scan.com, you will also have the support of your clinician, who will carefully go through the results with you and provide advice and guidance on the next steps. They are there to support you throughout the process and answer any questions you may have.

It’s also important to remember that serious conditions revealed by a chest X-ray are relatively rare, especially if you don't have any significant risk factors. For instance, lung cancer is diagnosed in only about 78 out of 100,000 individuals every year in the UK, and rates are expected to fall further.

Even if your doctor does find an abnormality in your lungs, it may be due to a minor or treatable condition, such as a respiratory infection or a benign growth.

Chest X-ray clear, but still coughing - what does that mean?

It’s possible to have a clear X-ray but still have a nagging or stubborn cough that won’t go away, and it can be down to one of several causes. Here are just a handful of factors that can cause a chronic cough without showing up on a chest X-ray:

Viral illness: A viral respiratory infection such as the common cold, flu, or COVID-19 can cause a persistent cough that lasts weeks or months. The UK is currently facing a 100-day cough (whooping cough or pertussis) outbreak, which causes a persistent cough in hundreds of children and adults every month.
Post-nasal drip: A respiratory infection can also cause a build-up of catarrh that drips slowly down your throat, causing irritation and cough. It usually clears up by itself but sometimes needs medical attention and treatment.
Smoking: Chronic coughing is common in smokers. The best thing you can do for your health is give up smoking.
Certain medications: Some blood pressure medications (Angiotensin Converting Enzyme (ACE) Inhibitors) can cause a dry, hacking cough that doesn’t go away. Speak to your doctor about changing your medication if this happens to you.
Acid reflux (Gastroesophageal Reflux Disease or GERD): People with GERD can experience frequent nighttime coughing or coughing after meals. Talk to your doctor about medications that may help.
Asthma, chronic obstructive pulmonary disease (COPD) or bronchial issues: These conditions may not always appear clearly on a standard chest X-ray but can still cause coughing.
Irritations and allergies: Hay fever and allergies to pet dander, dust or environmental pollutants can cause a chronic dry cough, especially if you have asthma.

If you've been suffering from a persistent cough that has lasted several weeks, getting a chest X-ray is a good idea. An X-ray can help identify the cause, whether it's an infection like pneumonia, an abnormality such as fluid buildup, a lung mass, or another underlying condition. While a clear X-ray is reassuring, you can still experience a lingering cough due to viral illnesses, acid reflux, or allergies.

Booking a chest X-ray through a trusted medical imaging provider like Scan.com can help you take the first step towards relief from a persistent cough. If you’re unsure whether you need a chest X-ray, our clinicians can guide you based on your specific symptoms and medical history in a one-to-one consultation with no obligation to book afterwards.