cytology

For more information on cytology, visit Britannica.com.

Key Terms: Biopsy, Cytology/cytopathology, Fine needle aspiration.

Definition

Cytology is the examination of individual cells and small clusters of cells, and may be used for the diagnosis and screening of diseases, including cancers. Cytology also refers to the study of diseases at the cellular level. For diagnosing diseases such as cancer, cytology may be referred to as cytopathology.

Purpose

Diagnostic tests are used to detect a disease in individuals who have signs, symptoms, or some other abnormality that indicates a disease. A screening test identifies those who might have a certain disease, sometimes before they develop any symptoms, but does not absolutely prove the disease is present. If a screening test is positive, a diagnostic test can be used as follow-up to verify the diagnosis.

Precautions

Procedures to gather cells for cytology are often less invasive than other forms of biopsy, and therefore may cause less discomfort, be less likely to result in serious complications, and cost less to perform. In some situations, however, where a piece of tissue is removed rather than individual cells, a different type of biopsy may be required to confirm the cytologic diagnosis.

Description

Samples for cytology can be obtained in more than one way. Fine needle aspiration (FNA) is a type of biopsy in which tumor samples are taken through thin needles.

Scrape or brush cytology is another technique in which cells are scraped or brushed from the organ or tissue being tested. Samples from the esophagus, stomach, bronchi (breathing tubes that lead to the lungs), mouth, and cervix (Pap smear) can be obtained using this type of procedure.

Liquid-based cytology has been introduced in Great Britain as an alternative to the scrape method for collecting cervical cells for Pap smears. It is considered more comfortable and as effective by those who have introduced the method.

How a cytology sample is processed depends on what type of sample it is. A doctor can smear a sample directly on a glass microscope slide. The slide is then stained and viewed by a cytopathologist. In other cases, the fluid is concentrated before being smeared and stained on a slide. This is especially useful for dilute samples such as those from body cavities.

Most routine cytology results are available one or two days after the sample is received in the laboratory. There are many reasons why some results take longer to return, such as if special stains are required to confirm a diagnosis.

Preparation, Aftercare, and Risks

Cytology analysis is performed on cells gathered during diagnostic procedures. The preparation, aftercare, and risks depend on the procedure used to gather the cells.

Normal Results

A cytopathologist examines the cells through a microscope and identifies the normal and abnormal cells on the slide using a microscope. Normal results generally indicate no sign of cancer.

Questions to Ask the Doctor

• What is a cytology test?
• How accurate is a cytology test?
• How long will it take to get cytology test results?

Abnormal Results

A cytopathologist examines the cells through a microscope. Abnormal cells may show signs that point to a possible diagnosis of cancer.

Resources

Periodicals

Cooper, Maggie. "Liquid Based Cytology: It's Been Approved as the Modern Replacement to the Conventional Smear Test, But What is Liquid Based Cytology?" Primary Health Care March 2004: 22–26.

Dahlstrom, Jane E., Gillian M. Langdale-Smith, and Daniel T. James. "Fine Needle Aspiration Cytology of Pulmonary Lesions: A Reliable Diagnostic Test." Pathology 33 (2001): 13-16.

Organizations

American Cancer Society. 1599 Clifton Road NE, Atlanta, GA 30329. (404) 320-3333. .

American Society for Clinical Pathologists (ASCP). 2100 West Harrison Street, Chicago, IL 60612. (312) 738-1336. .

American Society for Cytopathology (ASC). 400 West 9th Street, Suite 201, Wilmington, DE 19801. (302) 429-8802. .

College of American Pathologists (CAP). 325 Waukegan Road, Northfield, IL 60093. (800) 323-4040. .

International Academy of Cytology (IAC). 1640 East 50th Street, Ste. 20C, Chicago, IL 60615-3161. (773) 955-1406. .

—Laura Ruth, Ph.D.; Teresa G. Odle

The study of the anatomy, physiology, pathology, and chemistry of a cell.

The study of the structure and function of cells.

Cytology is the study of cellular structure based on microscopic techniques. Cytology became a separate branch of biology in 1892, when the German embryologist Oscar Hertwig (1849-1922) proposed that organismic processes are reflections of cellular processes.

A specialist in cytology.

The scientific study of cells.