Is Pleural Fluid Analysis?
Pleural fluid analysis is also known as thoracentesis. It’s a procedure used
to drain excess fluid from the space outside of the lungs but inside the chest
cavity. Normally, this area contains about 20 milliliters of clear or yellow
If there’s excess fluid in this area, it can cause symptoms such
as shortness of breath and coughing. An excess of pleural fluid, known as pleural effusion or pleurisy, will show up on chest X-ray
Your surgeon will perform pleural fluid analysis by inserting a
hollow needle or catheter into the space between two ribs in your back. This
space between two ribs is called the intercostal space. The procedure typically
takes place under local anesthesia. Once your surgeon has drained the excess
fluid, they’ll send it to the laboratory to determine the cause of the fluid
Pleural Fluid Analysis Is Used
Surgeons perform pleural fluid analysis to determine the cause of
the fluid buildup around your lungs. When the cause is known, thoracentesis may
still be used to eliminate discomfort, allowing you to breathe more easily.
Pleural fluid analysis is used with caution if you’re taking blood
thinners, such as warfarin
(Coumadin). Depending on the medication you’re taking your doctor will
determine how long you need to stop taking the medication before the procedure.
The procedure is generally avoided if you have severe clotting
problems or if you have a known history or clear signs of heart failure.
Pleural Fluid Analysis Is Performed
Pleural fluid analysis is performed under local anesthetic by a
surgeon in a hospital or same-day surgery setting. Before the procedure, you
can expect to have a chest X-ray, an ultrasound of your chest, and blood tests
to confirm that your blood is clotting normally.
When you arrive for the test, you’ll be asked to change into a
hospital gown. You’ll sit on the edge of an armless chair or on a bed. The technician
will help you lean forward so that your arms and head rest on a small table in
front of you. It’s important to remain as still as possible during the
procedure. The technician will cleanse the skin of your side and back with an
antiseptic, which may feel cold.
Your surgeon will check the preparations and give you an
injection of a local anesthetic. You can expect the injection to sting but only
for a short while. The area in the back of your ribs will go numb. After
numbness occurs, your surgeon will insert a large, hollow needle between your
ribs so that the excess fluid can drain into collection bottles. As the fluid
drains, you may experience some discomfort or a strong urge to cough. The
procedure typically takes about 15 minutes to complete.
The fluid is then sent to a laboratory for further analysis.
The lab classifies your fluid buildup as either exudate or
cloudy in appearance, and it normally contains high levels of protein and
cholesterol. It’s most commonly the result of an inflammation caused by an
infection of the lungs, such as pneumonia or tuberculosis. More rarely, it’s a
symptom of cancer.
Transudate, on the
other hand, is a clear fluid that contains little or no protein and low levels
of cholesterol. It usually signifies the failure of an organ such as the liver
Your treatment will depend on the underlying cause of the pleural
effusion. Your doctor may give you a medication and a diet to improve your
heart function. You may receive antibiotics to clear up a stubborn infection.
If the pleural fluid analysis suggests cancer, your surgeon will
probably suggest further tests including a lung biopsy.
of Pleural Fluid Analysis
Although it’s invasive, thoracentesis is considered a minor
procedure and requires no special follow-up care. The risks are rare, but they
- a pneumothorax, which is a partial or complete
collapse of your lung
- an infection at the puncture site
- an accidental puncture wound to the liver or
spleen (very rare)
- a buildup of excess fluid again, depending on
According to the Cleveland Clinic, pneumothorax occurs in about 10
percent of people who undergo pleural fluid analysis. A small pneumothorax
will heal by itself, but a larger one usually requires hospitalization and
After the procedure is completed and the needle is withdrawn, the
technician will place pressure on the wound to control any bleeding. Your
doctor will then apply bandages or a dressing, which you’ll wear for the next
day or so.
Depending on the surgeon, you may be asked to stay for an hour of
observation. When you’re released from the facility, you can go back to your normal
activities immediately unless your surgeon tells you otherwise.