Exfoliated cells in body tissues and fluid are studied to determine the types of cells present and to diagnose malignant and premalignant conditions. The staining technique developed by Dr. George N. Papanicolaou has been especially useful in diagnosis of malignancy and is now used routinely in the cytologic study of the female genital tract as well as in many types of nongynecologic specimens.
Some cytologic specimens (e.g., smears of the mouth, genital tract, nipple discharge) are relatively easy to obtain for study. Other samples (e.g., amniotic fluid, pleural effusions, cerebrospinal fluid [CSF]) are from less accessible sources, and special techniques, such as fine-needle aspiration (FNA), are required for collection. Histologic samples may be obtained by biopsy during surgery or during outpatient diagnostic procedures such as endoscopy. In all studies, the source of the sample and its method of collection must be documented so that the evaluation can be based on complete information.
Specimens for cytologic and histologic study usually consist of many different cells. Some are normally present, whereas others indicate pathologic conditions. Cells normally observed in one sample may, under certain conditions, be indicative of an abnormal state when observed elsewhere. All specimens are examined for the number of cells, cell distribution, surface modifications, size, shape, appearance and staining properties, functional adaptations, and inclusions. The cell nucleus is also examined. Any increases or decreases from normal values are noted.
Gynecologic specimens may be smeared and fixed in 95% alcohol. Some types of spray fixative are also available. (Gynecologic specimens collected using the liquid-based technique are collected in special solution.) Nongynecologic specimens are generally collected without preservative. They may be placed in saline, and they must be handled carefully to prevent drying or degeneration. Check with your individual laboratory for collection requirements. It is important that all cytology specimens be sent to the laboratory as soon as they are obtained to prevent disintegration of cells or any other process that could cause alteration of the material for study.
Clinical Alert
Test analysis and results depend on the quality of the specimen obtained.
Specimens collected from patients in isolation should be clearly labeled on the specimen container (patient’s name, date, and test[s] ordered) and requisition form with appropriate warning stickers. The specimen container should then be placed inside two sealed, protective biohazard bags before it is transported to the laboratory.
The U.S. Occupational Safety and Health Administration requires that all specimens be placed in a secondary container before transportation to the laboratory. Most laboratories prefer plastic biohazard bags. Requisitions should be kept on the outside of the bag or in a separate compartment in the biohazard bag, if available.
Results of cytologic studies are commonly reported as:
Inflammatory
Benign
Atypical
Suspicious for malignancy
Positive for malignancy (in situ versus invasive)