Effusions and Cytology

Diagnosis of diseases based on examination of individual cells and small clusters of cells, called cytology or cytopathology, has become increasingly important in cancer diagnosis. While the pieces of tissue in biopsy samples may be as small as 1/16 inch or much larger (several inches), the individual cells and the cell clusters in cytology samples are placed in fluid and are usually too small to see without a microscope. Sometimes, only one drop of blood or tissue fluid is taken. On the other hand, some pleural fluid or peritoneal fluid cytology samples may include a quart or more of fluid.

A cytology specimen usually is easier to obtain, causes less discomfort to the patient, is less likely to result in serious complications, and is less expensive than a tissue biopsy. The disadvantage is that a biopsy result is more accurate.

Cytology tests may be used in two ways -- for diagnosis or for screening. Diagnostic tests are used for people who have signs, symptoms, or some other indication that a particular disease such as cancer is likely to be present. The purpose of a diagnostic test is to determine if a disease is present and, if so, to classify it precisely and accurately. A screening test is used to identify people who might have a certain disease even before they develop symptoms of that condition. A

Fine needle aspiration biopsy (FNA): FNA is sometimes considered a cytology test and is sometimes called a biopsy.

Additional Information

"Malignant Pleural Therapy: Intrapleural Therapy," Daniel L. Miller, MD, Assoc. Prof. of Surgery, Emory University and Clinic, Atlanta, Georgia. Presented at MARF conference in Las Vegas, Oct. 7, 2005

Immunohistochemistry in the distinction between malignant mesothelioma and pulmonary adenocarcinoma: a critical evaluation of new antibodies (10/14/02))