The UCLA Lung Cancer Program is comprised of a multidisciplinary team of experts who are dedicated to the prevention, detection, treatment, and research of lung cancer.
Schedule an Appointment
Lung Cancer Home
About Us
Our Expert Team
Our Services
Thoracic Surgery
First Visit for Patients
Patient Education
Clinical Trials
For Referring Physicians
Lung Screening Clinic
Insurance Questions
Contact Us
Giving / Donations
Site Map

Schedule an Appointment

Patient Education

Patient Education - Lung Cancer Program at UCLA

Educating yourself about lung cancer:

Procedures: Pleural tap; Thoracentesis

The major features of the lungs include the bronchi, the bronchioles and the alveoli. The alveoli are the microscopic blood vessel-lined sacks in which oxygen and carbon dioxide gas are exchanged.Pleural tap; Thoracentesis


Thoracentesis is a procedure to remove fluid from the space between the lining of the outside of the lungs (pleura) and the wall of the chest. Normally, very little fluid is present in this space. An accumulation of excess fluid between the layers of the pleura is called a pleural effusion.

Alternative Names

Pleural fluid aspiration; Pleural tap; Thoracentesis

How the Test is Performed

A small area of skin on your chest or back is washed with a sterilizing solution. Some numbing medicine (local anesthetic) is injected in this area. A needle is then placed through the skin of the chest wall into the space around the lungs called the pleural space. Fluid is withdrawn and collected and may be sent to a laboratory for analysis (pleural fluid analysis).

How to Prepare for the Test

No special preparation is needed before the procedure. A chest x-ray is may be performed before and after the test.

Do not cough, breathe deeply, or move during the test to avoid injury to the lung.

How the Test Will Feel

You will on a bed or sit on the edge of a chair or bed with your head and arms resting on a table. The skin around the procedure site is disinfected and the area is draped. A local anesthetic is injected into the skin. The thoracentesis needle is inserted above the rib into the pleural space.

There will be a stinging sensation when the local anesthetic is injected, and you may feel a sensation of pressure when the needle is inserted into the pleural space.

Inform your health care provider if you develop shortness of breath or chest pain.

Why the Test is Performed

The test is performed to determine the cause of the fluid accumulation or to relieve the symptoms associated with the fluid accumulation.

Normal Results

Normally the pleural cavity contains only a very small amount of fluid.

What Abnormal Results Mean

The analysis of the fluid will indicate possible causes of pleural effusion such as infection, cancer, heart failure, cirrhosis, and kidney disease. If infection is suspected, a culture of the fluid is often done to determine whether microorganisms are present and if so, to identify them.

Additional conditions under which the test may be performed include the following:

  • Pneumonia
  • Hemothorax
  • Pulmonary veno-occlusive disease
  • Pancreatitis
  • Pulmonary embolism
  • Thyroid disease
  • Collagen vascular disease
  • Asbestos-related pleural effusion
  • Drug reactions


  • Pneumothorax (collapse of the lung)
  • Fluid re-accumulation
  • Pulmonary edema
  • Bleeding
  • Infection
  • Respiratory distress


A chest x-ray is often done after the procedure to detect possible complications.

Review Date: 8/7/2006
Reviewed By: David A. Kaufman, M.D., Assistant Professor, Division of Pulmonary, Critical Care & Sleep Medicine, Mount Sinai School of Medicine, New York, NY. Review provided by VeriMed Healthcare Network.

A.D.A.M. qualityA.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission ( URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics and subscribes to the principles of the Health on the Net Foundation (

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Call 911 for all medical emergencies. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- 2007 A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

A.D.A.M. logo


Diseases of the Lung:

Signs and symptoms:

Tests and studies: