Pleural fluid smear is a laboratory procedure to check for bacteria, fungi, or abnormal cells in the fluid that may be found in the space around the lungs (called a pleural effusion).

How the Test is Performed

A health care provider examines a sample of pleural fluid under the microscope. If the smear detects bacteria or fungi, other methods may be used to identify those organisms.

How the Test Will Feel

The sample is obtained through a procedure called thoracentesis. For information about this test and its risks, see thoracentesis.

Why the Test is Performed

The test is performed if you have a pleural effusion and its cause is not known, especially if the health care provider suspects an infection or cancer.

Normal Results

Normally, no bacteria or fungi are present in the pleural fluid.

Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

What Abnormal Results Mean

Positive results may indicate that bacteria or cancer cells are present. Other tests can help identify the specific type of infection or cancer.

Risks

See: Thoracentesis