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Thoracentesis

Results

Thoracentesis is a procedure to remove fluid from the space between the lungs and the chest wall called the pleural space. Results from a lab are usually available in 1 to 2 working days. If the fluid is being tested for an infection, such as tuberculosis, results may not be available for several weeks.

Thoracentesis
Normal:

A small amount of clear, colorless, or pale yellow pleural fluid, usually less than 20 mL (0.7 fl oz), is normally present. No infection, inflammation, or cancer is found.

Abnormal:

A large amount of pleural fluid is present.

Fluid may be labeled as either a transudate or an exudate. The difference between these two types of fluid has to do with the amount of protein and other substances found in the fluid.

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

What To Think About

  • Thoracentesis may not be done for people who have:
  • A pleural biopsy may be done at the same time as a thoracentesis to collect a sample of tissue from the inner lining of the chest wall.
  • Thoracentesis may be done before another procedure called pleurodesis. During this procedure, a chemical or medicine (talc or doxycycline) is put into the pleural space, which triggers an inflammatory reaction over the surface of the lung and inside the pleural space. This in turn causes the layer of pleura attached to the lung to stick to the layer of pleura on the inside of the chest wall. This takes away the space between the pleura and prevents or reduces the collection of more pleural fluid. Pleurodesis may be done when fluid collects in the chest more than one time and the reason for the fluid buildup cannot be corrected.

WebMD Medical Reference from Healthwise

Last Updated: November 01, 2012
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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