Pleural Fluid Sampling (or Thoracentesis)

What is the test?

Some infections and diseases cause fluid to accumulate in the space between the lung and the rib cage or between the lung and the diaphragm. This collection of fluid is called a pleural effusion. A pleural effusion might be detected on a chest x-ray. Sampling this fluid is important because it enables doctors to understand what caused the fluid to collect and how to treat the problem. The fluid can be sampled with a needle.

How do I prepare for the test?

You will need to sign a consent form giving your doctor permission to perform this test. Some patients have this test done in a doctor's office, while others are admitted to the hospital for it. Generally your doctor will decide whether you need to be in the hospital based on your medical condition. A chest x-ray or an ultrasound is done before the procedure.

Tell your doctor if you have ever had an allergic reaction to lidocaine or the numbing medicine used at the dentist's office. If you take aspirin, nonsteroidal anti-inflammatory drugs, or other medicines that affect blood clotting, talk with your doctor. It may be necessary to stop or adjust the dose of these medicines before your test.

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