Pleural fluid smear

• 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 Values

  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.

• What the risks are

  See: Thoracentesis

• References

  Broaddus VC, Light RW. Pleural effusion. In: Mason RJ, Murray J, Broaddus VC, Nadel J, eds. Textbook of Respiratory Medicine. 4th ed. Philadelphia, Pa: Saunders Elsevier;2005:chap 68.

Review Date: 10/14/2009

Reviewed By: Andrew Schriber, MD, FCCP, Specialist in Pulmonary, Critical Care, and Sleep Medicine, Virtua Memorial Hospital, Mount Holly, New Jersey. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.