Skip to main content Skip to navigation

Thoracentesis – Indications, Procedures, Results

Pleural fluid aspiration; Pleural tap

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.

How the Test is Performed

The test is done in the following way:

  • You sit on a bed or on the edge of a chair or bed. Your head and arms rest on a table.
  • The skin around the procedure site is cleaned. A local numbing medicine (anesthetic) is injected into the skin.
  • A needle is placed through the skin and muscles of the chest wall into the space around the lungs, called the pleural space. The health care provider may use ultrasound to find the best spot to insert the needle.
  • Fluid is drawn out with the needle.
  • The fluid may be sent to a laboratory for testing ( pleural fluid analysis ).

How to Prepare for the Test

No special preparation is needed before the test. A chest x-ray  or ultrasound will be done 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 feel a stinging sensation when the local anesthetic is injected. You may feel pain or pressure when the needle is inserted into the pleural space.

Tell your provider if you feel short of breath or have  chest pain .

Why the Test is Performed

Normally, very little fluid is in the pleural space. A buildup of too much fluid between the layers of the pleura is called a pleural effusion .

The test is performed to determine the cause of the extra fluid, or to relieve symptoms from the fluid buildup.

Normal Results

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

What Abnormal Results Mean

Testing the fluid will help your provider determine the cause of pleural effusion. Possible causes include:

  • Cancer
  • Liver failure
  • Heart failure
  • Low protein levels
  • Kidney disease
  • Trauma or post-surgery
  • Asbestos-related pleural effusion
  • Collagen vascular disease (class of diseases in which the body’s immune system attacks its own tissues)
  • Drug reactions
  • Collection of blood in the pleural space (hemothorax)
  • Lung cancer
  • Swelling and inflammation of the pancreas ( pancreatitis )
  • Pneumonia
  • Blockage of an artery in the lungs (pulmonary embolism)
  • Severely underactive thyroid gland

If your provider suspects that you have an infection, a culture of the fluid may be done to test for bacteria.

Risks

Risks may include any of the following:

  • Bleeding
  • Infection
  • Pneumothorax
  • Respiratory distress

Considerations

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

 

Frequently Asked Questions

Is this article a replacement for a doctor?

No. It is educational content only. Patients should consult a qualified clinician for diagnosis and treatment.

When should I seek urgent care?

Seek urgent care for severe symptoms, rapidly worsening condition, breathing difficulty, severe pain, neurological changes, or any emergency warning sign.

References

Add references, clinical guidelines, textbooks, journal articles, or trusted medical sources here. You can edit this area later with a custom field named _rx_references.

Written by Dr. Harun Ar Rashid, MD - Arthritis, Bones, Joints Pain, Trauma, and Internal Medicine Specialist

Dr. Md. Harun Ar Rashid, MPH, MD, PhD, is a highly respected medical specialist celebrated for his exceptional clinical expertise and unwavering commitment to patient care. With advanced qualifications including MPH, MD, and PhD, he integrates cutting-edge research with a compassionate approach to medicine, ensuring that every patient receives personalized and effective treatment. His extensive training and hands-on experience enable him to diagnose complex conditions accurately and develop innovative treatment strategies tailored to individual needs. In addition to his clinical practice, Dr. Harun Ar Rashid is dedicated to medical education and research, writing and inventory creative thinking, innovative idea, critical care managementing make in his community to outreach, often participating in initiatives that promote health awareness and advance medical knowledge. His career is a testament to the high standards represented by his credentials, and he continues to contribute significantly to his field, driving improvements in both patient outcomes and healthcare practices. Born and educated in Bangladesh, Dr. Rashid earned his BPT from the University of Dhaka before pursuing postgraduate training internationally. He completed his MD in Internal Medicine at King’s College London, where he developed a special interest in inflammatory arthritis and metabolic bone disease. He then undertook a PhD in Orthopedic Science at the University of Oxford, conducting pioneering research on cytokine signaling pathways in rheumatoid arthritis. Following his doctoral studies, Dr. Rashid returned to clinical work with a fellowship in interventional pain management at the Rx University School of Medicine, refining his skills in image-guided joint injections and minimally invasive pain-relief techniques.