Cytology is the examination of a single cell type, as often found in fluid specimens. It's mainly used to diagnose or screen for cancer. It's also used to screen for fetal abnormalities, for pap smears, to diagnose infectious organisms, and other screening and diagnostic areas.
The cells to be examined may be taken through the following methods:
Scraping or brushing the tissue surface
Fine-needle aspirations (removing cells by drawing them through a fine needle)
Other types of tissue biopsy
Cytology is different from histology. Cytology generally involves looking at a single cell type. Histology is the examination of an entire block of tissue.