Cytopathology may be a branch of pathology that studies and diagnoses diseases on the cellular level. The discipline was founded by George Nicolas Papanicolaou in 1928. Cytopathology is usually used on samples of free cells or tissue fragments, in contrast to histopathology, which studies whole tissues. Cytopathology is usually, less precisely, called "cytology", which suggests "the study of cells". Cytopathology is usually wont to investigate diseases involving a good range of body sites, often to assist within the diagnosis of cancer but also within the diagnosis of some infectious diseases and other inflammatory conditions. For example, a standard application of cytopathology is that the cervical smear, a screening tool wont to detect precancerous cervical lesions which will cause cervical cancer. Cytopathologic tests are sometimes called smear tests because the samples could also be smeared across a glass slide for subsequent staining and microscopic examination. However, cytology samples could also be prepared in other ways, including cytocentrifugation. Different types of smear tests can also be used for cancer diagnosis. In this sense, it's termed a smear.