Lung Cancer Prevention and Early Detection

+ -Text Size


Exams and tests to look for lung cancer

If your doctor thinks you might have lung cancer based on the results of a screening test or because of symptoms you are having, he or she will do exams and tests to find out for sure.

Medical history and physical exam

Your doctor will want to take a medical history to check for any risk factors and to learn more about any symptoms you are having. Your doctor will also examine you for signs of lung cancer or other health problems.

If the results of the history and physical exam suggest you might have lung cancer, more involved tests will be done (see below).

Tests that might be used to look for lung cancer

Sputum cytology

For this test, a sample of sputum (mucus you cough up from the lungs) is looked at under a microscope to see if it contains cancer cells. The best way to do this is to get early morning samples from you 3 days in a row. This test is more likely to help find cancers that start in the major airways of the lung, such as most small cell lung cancers and squamous cell lung cancers. It may not be as helpful for finding other types of non-small cell lung cancer.

Chest x-ray

If you have symptoms that might be due to lung cancer, this is often the first test your doctor will do to look for any masses or spots on the lungs. Plain x-rays of your chest can be done at imaging centers, hospitals, and even in some doctors’ offices. If the x-ray is normal, you probably don’t have lung cancer (although some lung cancers may not show up on an x-ray). If something suspicious is seen, your doctor may order more tests.

Computed tomography (CT) scan

A CT (or CAT) scan is more likely to show lung tumors than routine chest x-rays. A CT scan can also provide precise information about the size, shape, and position of any lung tumors and can help find enlarged lymph nodes that might contain cancer that has spread from the lung.


Before the CT scan, you may be asked to drink a contrast solution or you may get an injection of a contrast solution through an IV (intravenous) line. This helps better outline structures in your body. The contrast may cause some flushing (a feeling of warmth, especially in the face). Some people are allergic and get hives. Rarely, more serious reactions like trouble breathing or low blood pressure can occur. Be sure to tell the doctor if you have any allergies or if you ever had a reaction to any contrast material used for x-rays.

A CT scanner has been described as a large donut, with a narrow table that slides in and out of the middle opening. You will need to lie still on the table while the scan is being done. CT scans take longer than regular x-rays, and you might feel a bit confined by the ring while the pictures are being taken.

Further tests if you have an abnormal screening test result

It is common for a low-dose CT scan of the lungs to show small, abnormal areas (called nodules or masses) in the lungs, especially in current or former smokers. Most lung nodules seen on CT scans are not cancer. They are more often the result of old infections, scar tissue, or other causes. But tests are often needed to be sure a nodule is not cancer.

Most often the next step is to get a repeat CT scan to see if the nodule is growing over time. The time between scans might range anywhere from about a month to a year, depending on how likely your doctor thinks it is that the nodule could be cancer. This is based on the size, shape, and location of the nodule, as well as whether it appears to be solid or filled with fluid. If the nodule is larger, your doctor might also want to get another type of imaging test called a positron emission tomography (PET) scan, which can often help tell if it is cancer.

If the second scan shows that the nodule has grown, or if the nodule has other concerning features, your doctor will want to get a sample of it to check it for cancer cells (called a biopsy). This can be done in different ways.

  • The doctor might pass a long, thin tube (called a bronchoscope) down your throat and into the airways of your lung to reach the nodule. A small, hollow needle on the end of the bronchoscope can be used to get a sample of the nodule.
  • If the nodule is in the outer part of the lung, the doctor might pass a thin, hollow needle through the skin of the chest wall and into the nodule to get a sample.
  • If there is a higher chance that the nodule is cancer (or if the nodule can’t be biopsied with a needle), surgery might be done to remove the nodule and some surrounding lung tissue. Sometimes larger parts of the lung might be removed at the same time as well.

These types of tests, biopsies, and surgeries are described in more detail in our documents Lung Cancer (Non-Small Cell) and Lung Cancer (Small Cell) as are the options for treatment if lung cancer is found.

Further tests if you have possible signs or symptoms of lung cancer

If your doctor is concerned you might have lung cancer because of signs or symptoms you are having, a chest x-ray or chest CT scan to look for tumors in the lung is likely to be the next step. Other tests that might be done include having you cough up sputum (phlegm) to have it looked at for cancer cells, or having a bronchoscopy, where the doctor puts a long, thin tube down your throat and into your lungs to look for anything abnormal.

If any of these tests are suspicious for cancer, further tests such as a biopsy or even surgery will likely be needed to get samples from any tumors.


Last Medical Review: 06/26/2013
Last Revised: 02/21/2014