Health Encyclopedia

Cytology exam of pleural fluid

Definition

A cytology exam of pleural fluid is a laboratory test to detect cancer cells and certain other cells in the fluid from the area that surrounds the lungs. This area is called the pleural space. Cytology means the study of cells.

Alternative Names

Pleural fluid cytology; Lung cancer - pleural fluid

How the Test is Performed

A sample of fluid from the pleural space is needed. The sample is taken using a procedure called thoracentesis.

The procedure 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.
A small area of skin on your back is cleaned. Numbing medicine (local anesthetic) is injected in this area.
The doctor inserts a needle through the skin and muscles of the chest wall into the pleural space.
Fluid is collected.
The needle is removed. A bandage is placed on the skin.

The fluid sample is sent to a laboratory. There, it is examined under the microscope to determine what the cells look like and whether they are abnormal.

How to Prepare for the Test

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

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

Why the Test is Performed

A cytology exam is used to look for cancer and precancerous cells. It may also be done for other conditions, such as identifying systemic lupus erythematosus cells. Occasionally, microorganisms can be seen in cytology too, but in general, they are best identified by culture.

Your doctor may order this test if you have signs of fluid buildup in the pleural space. This condition is called pleural effusion. The test may also be done if you have signs of lung cancer.

Normal Results

Normal cells are seen.

What Abnormal Results Mean

In an abnormal result, there are cancerous (malignant) cells. This may mean there is a cancerous tumor. This test most often detects:

Breast cancer
Lymphoma (cancer of the lymph system)
Lung cancer
Ovarian cancer
Stomach cancer

Risks

Risks are related to thoracentesis and may include:

Bleeding
Infection
Collapse of the lung (pneumothorax)
Difficulty breathing

References

Blok BK. Thoracentesis. In: Roberts JR, Custalow CB, Thomsen TW, eds. Roberts and Hedges' Clinical Procedures in Emergency Medicine and Acute Care. 7th ed. Philadelphia, PA: Elsevier; 2019:chap 9.

Cibas ES. Pleural, pericardial, and peritoneal fluids. In: Cibas ES, Ducatman BS, eds. Cytology. 5th ed. Philadelphia, PA: Elsevier; 2021:chap 4.

Chernecky CC, Berger BJ. Thoracentesis - diagnostic. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6th ed. St Louis, MO: Elsevier Saunders; 2013:1052-1135.

Ruhl TS, Good JL. Thoracentesis. In: Fowler GC, Choby BA, Iyengar D, et al, eds. Pfenninger and Fowler's Procedures for Primary Care. 4th ed. Philadelphia, PA: Elsevier; 2020:chap 218.

Review Date:7/31/2022
Reviewed By:Denis Hadjiliadis, MD, MHS, Paul F. Harron Jr. Professor of Medicine, Pulmonary, Allergy, and Critical Care, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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-A.D.A.M., Inc. Any duplication or distribution of the information contained herein is strictly prohibited.

The Agency for Health Care Administration (Agency) and this website do not claim the information on, or referred to by, this site is error free. This site may include links to websites of other government agencies or private groups. Our Agency and this website do not control such sites and are not responsible for their content. Reference to or links to any other group, product, service, or information does not mean our Agency or this website approves of that group, product, service, or information.

Additionally, while health information provided through this website may be a valuable resource for the public, it is not designed to offer medical advice. Talk with your doctor about medical care questions you may have.