Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Lung Disease & Respiratory Health Center

Font Size



Thoracentesis is generally a safe procedure. A chest X-ray may be done right after the procedure to make sure that no complications have occurred. Complications may include:

  • A partial collapse of the lung (pneumothorax). This may occur if the needle used to remove the pleural fluid punctures the lung, allowing air to flow into the pleural space.
  • Pulmonary edema, which may occur if a large amount of fluid is removed.
  • Infection and bleeding.
  • Damage to the liver or spleen, though this is rare.


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 1 2

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.


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.

WebMD Medical Reference from Healthwise

Last Updated: September 09, 2014
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.

Today on WebMD

man coughing
You may not even know you have it.
blood clot
Signs of this potentially fatal complication.
man coughing
When a cold becomes bronchitis.
human lungs
Causes behind painful breathing, fluid buildup.

chest x-ray
Bronchitis Overview
Copd Myth Fact Quiz
Energy Boosting Foods

woman coughing
Lung xray and caduceus