Cytology is a discipline within Pathology that studies and diagnoses disease on a cellular level. Cytology can be used as either a screening tool or as a diagnostic tool.

Cytology screening aims to detect early changes in cells in symptomless individuals. Individuals are routinely tested for the presence of a disease to reduce the possible risk of developing a malignant lesion at a later date.

Diagnostic cytology is used to diagnose a condition when an individual presents with symptoms. Cytology samples can be obtained by either non invasive or minimally invasive techniques. These techniques can be classified into exfoliative or aspiration methods. Exfoliative cytology is the collection of cells that have spontaneously shed into a body cavity or from the surface of tissue. Aspiration cytology involves the removal of cells from a lesion or mass using a fine needle and a syringe.