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Pleural Fluid Culture

Definition

Pleural fluid culture is a test that looks at a sample of fluid from the space around the lungs to find and identify disease-causing microorganisms.

Alternative Names

Culture - pleural fluid

How the test is performed

A procedure called thoracentesis is done to obtain a sample of pleural fluid. The health care provider cleans a small area on your chest with germ-killing (antibacterial) soap and numbs the area with local pain-killing medicine (anesthetic). A needle is placed between the ribs, and a sample of fluid is taken from the chest.

The sample is placed on special plates that contain a substance to help the microorganisms in the fluid grow. When colonies of microorganisms are big enough, the health care provider does a series of tests to identify the infection-causing microorganisms.

How to prepare for the test

It is important not to cough, breathe deeply, or move when the fluid sample is being taken. There is no other special preparation for the test.

How the test will feel

You may feel a stinging sensation when the anesthetic is injected. You may feel some pressure and slight pain in the area when the thoracentesis needle enters the pleural space. You may have a chest x-ray after the test to make sure the test did not affect the lung tissue or function.

Why the test is performed

The test is performed when the health care provider suspects an infection of the pleural space, or when a chest x-ray reveals an abnormal collection of pleural fluid.

Normal Values

Normally, no microorganisms are present in the pleural fluid.

Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

What abnormal results mean

Abnormal results may indicate:

  • Congestive heart failure
  • Empyema
  • Lung abscess
  • Pneumonia
  • Tuberculosis

What the risks are

There is a risk of internal bleeding into the lung and collapsed lung (pneumothorax). Serious complications are extremely rare.

References

Celli BR. Diseases of the diaphragm, chest wall, pleura, and mediastinum. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 100.

Review Date: 12/1/2009

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