Pneumonia is a lung infection generally caused by bacteria, viruses or fungi. The infection, which can affect one or both lungs, leads to fluid or pus buildup in the air sacs. The symptoms are often triggered following another illness, such as the flu. Diagnosing pneumonia requires one or more simple procedures by a physician.
The first step in diagnosing pneumonia often begins with a physical exam. Some of the symptoms of pneumonia directly affect the lungs, such as shortness of breath and fluctuating chest pain. According to the Mayo Clinic, this simple exam involves your doctor listening to your lungs for "abnormal bubbling or crackling sounds."
If pneumonia is suspected, the diagnosis can generally be confirmed with a chest X-ray. The X-ray can also determine where the infection is located and the extent of the condition. WebMD explains that a chest X-ray can help your doctor find the underlying cause of the pneumonia and show other complications that may be affecting your lungs, such as fluid buildup and acute bronchitis. The disadvantage of using X-rays to diagnose pneumonia is that they may not be accurate-especially in the early stages of the condition.
Blood and mucus tests
Blood and mucus tests are performed to check white cell count. These tests also help identify viruses and bacteria that may have led to the pneumonia. A rapid urine test identifies some forms of bacteria that cause pneumonia but will not identify pneumonia caused by viruses or fungi.
The American Lung Association mentions other testing that may be performed to measure how much oxygen is traveling through the bloodstream and how much is reaching the lungs. Testing of the arterial blood gases measures the amount of oxygen reaching your blood from the lungs. To measure how much oxygen is moving in the bloodstream, a small clip known as a pulse oximeter is attached to the end of the finger.
For hospitalized patients who are not responding well to antibiotics, more testing may be needed to diagnose pneumonia. One procedure known as a bronchoscopy allows a doctor to view the lungs' airways. The National Heart Lung and Blood Institute describes this procedure as the insertion of a flexible tube into the nose or mouth which is "passed down your throat into your airways." A light and camera at the end of the bronchoscope allows the doctor to see lung problems, including signs of infection, excess mucus and blockages.
To test for bacteria, viruses or fungi, your doctor may order a pleural fluid culture. According to the National Institutes of Health this test, known as a thoracentesis, is also used to "remove fluid from the space between the lining of the outside of the lungs (pleura) and the wall of the chest." This procedure is done by inserting a thoracentesis needle above the rib area into the pleural space. A thoracentesis will also show the excess fluid and the cause of the build-up.
Before any tests are performed, it is important to provide your doctor with your full medical history. While most cases of pneumonia are caused by bacteria, viruses or fungi, the Mayo Clinic explains that some cases are the result of inhalation of foreign matter into the lungs. This is often a concern for people with swallowing difficulties, which can coincide with other medical conditions, such as Parkinson's disease and seizure disorders.