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Pneumonia - Exams and Tests

Your doctor will usually diagnose pneumonia with:

  • Your medical history.
  • A physical exam.
  • A chest X-ray, which is almost always done to check for changes in the lungs that may mean pneumonia and to look for other causes of your symptoms. But an X-ray does not always show whether you have pneumonia, especially if it is done when you first get sick. In some cases, the X-ray results may:
    • Suggest the type of organism (bacterial, viral, or fungal) causing pneumonia.
    • Show complications of pneumonia, such as infection of the heart muscle or the sac surrounding the heart.
    • Show conditions that may occur with pneumonia, such as fluid in the chest cavity or a collapsed lung.
    • Reveal another condition, such as heart failure, lung cancer, or acute bronchitis.

Lab tests for pneumonia

The need for more tests often depends on how severe your symptoms are, your age, and your overall health. In general, the sicker you are, the more tests you may need. This is especially true for older adults and infants. One example of a test you may have is the arterial blood gas test.

Mucus test

If you are very ill, have severe shortness of breath, or have a condition that increases your risk (such as asthma or COPD), your doctor may test your mucus. Tests include a Gram stain and a sputum culture.

Rapid urine test

This test can identify some bacteria that cause pneumonia. This can help guide treatment for pneumonia.

HIV test

In people who have impaired immune systems, pneumonia may be caused by other organisms, including some forms of fungi, such as Pneumocystis jiroveci (formerly called Pneumocystis carinii). This fungus often causes pneumonia in people who have AIDS. Some doctors may suggest an HIV test if they think that Pneumocystis jiroveci is causing the pneumonia.

Other lung tests

If you have severe pneumonia, you may need other tests, including tests to check for complications and to find out how well your immune system is working.

    This information is produced and provided by the National Cancer Institute (NCI). The information in this topic may have changed since it was written. For the most current information, contact the National Cancer Institute via the Internet web site at http:// cancer .gov or call 1-800-4-CANCER.

    WebMD Medical Reference from Healthwise

    Last Updated: March 06, 2013
    This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
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