Your doctor will ask about your symptoms. If symptoms suggest pneumonia, your doctor will ask about your medical history, travel history, and other related exposures. This information may suggest what caused your pneumonia. A physical exam usually includes tapping on your chest and back. This may identify the presence of fluid or air trapped in your lungs. The doctor will also listen carefully to your chest and back with a stethoscope.

Your doctor may choose to order a variety of tests, such as:

Blood Tests —Complete blood count including the number and types of white blood cells may help determine whether you have a viral, bacterial, or fungal infection.

Blood Culture —This involves sending a blood sample to a laboratory where it can be processed to see if any organisms are growing. If there are organisms, they can often be identified, and tests can be run to determine what types of antibiotics can best eliminate them.

Urine Antigen Tests —This involves giving a urine sample to look for certain bacteria that could be causing the infection.

Pulse Oximetry —This test measures the amount of oxygen in your blood to get a sense of how ill you are.

Arterial Blood Gas —This blood test measures the concentration of certain substances in your blood, including oxygen, carbon dioxide, and pH. This test may be performed to determine whether you will be able to continue breathing on your own, or whether you may need treatment with additional oxygen or mechanical ventilation.

Sputum Culture —If you’re able to cough up a sample of sputum, it can be sent to a laboratory to examine it for the presence of specific organisms. If there are organisms in the sputum, they can often be identified, and a specific antibiotic can be ordered for you.

Chest X-ray —Chest x-ray may reveal signs of pneumonia. However, sometimes a patient will have clear-cut symptoms and signs of pneumonia on physical exam with a clear x-ray for the first couple of days. This may be the case if a patient is dehydrated.

Lung Ultrasound —An ultrasound may reveal signs of pneumonia. However, it may not detect a small percentage of lesions.

CT Scan —This imaging procedure may be required in some cases.

Bronchoscopy —In this procedure, a narrow, lighted scope is passed through your mouth or nose, down your bronchial tubes, and into your lungs. Your healthcare provider can examine your respiratory tract for signs of pneumonia. Samples of fluid and biopsies of tissue can be taken through the bronchoscope. These samples can be processed and examined in a laboratory to try to identify organisms that might be causing your pneumonia. This test is does not usually need to be performed.

Thoracentesis (Pleural Fluid Aspiration) —This invasive procedure is performed if pneumonia is complicated by fluid accumulation in the lung (pleural effusions). A needle can be passed through the chest, back, or between the ribs in order to withdraw excess fluid in the chest cavity. This fluid can be examined in a laboratory to identify organisms responsible for the pneumonia.