Topic Overview

Other tests for lung infections, such as pneumonia and acute bronchitis, may include:

• Blood tests or cultures. Blood tests may help tell whether antibodies to a specific organism that can cause pneumonia are present or whether specific viruses, such as influenza (flu) or respiratory syncytial virus (RSV), are present. Doctors can use blood cultures to test for bacteria in your bloodstream.
• Oximetry. An oximeter can estimate the amount of oxygen in your blood. A sensor in a cuff or clip is placed on the end of your finger. This sensor measures how much oxygen is in your blood. The oximeter machine shows the result.
• Arterial blood gases. An arterial blood gas test can measure the levels of oxygen in a sample of blood drawn from your artery. Doctors use this test to find out whether enough oxygen is getting into your bloodstream from your lungs.
• Bronchoscopy. Bronchoscopy is a visual examination of the tubes leading to your lungs. This test is usually done by a respirologist (lung specialist). He or she inserts a small, lighted device through your nose or mouth into the tubes leading to your lungs. During the procedure, the doctor can obtain samples of tissue, fluid, or mucus.
• Transtracheal mucus cultures (rarely done). Transtracheal sputum cultures are tests performed on a mucus sample obtained directly from your windpipe (trachea).
• Lung biopsy. A lung biopsy is a test done on a very small piece of lung tissue to look for conditions such as lung cancer or fibrous tissue in the lungs (pulmonary fibrosis). Your doctor obtains lung tissue by inserting a needle into your chest between two ribs or by using bronchoscopy.
• Thoracentesis. Thoracentesis involves puncturing the chest wall to obtain fluid from the space around the lungs. Fluid obtained during the test can be checked for signs of infection or cancer.
• Computed tomography (CT) scan. A CT scan uses X-rays to produce detailed pictures of structures inside your body. It may be used in people who are not responding to their treatment.