The brush biopsy, oral exfoliative cytology, is considered an adjunct diagnostic tool which uses a patented spiral-shaped stiff brush to remove epithelial cells for examination by a pathologist. The brush is firmly rolled over the lesion until bleeding points are observed signaling the epithelial tissues have been penetrated. The brush retrieves cells from all three tissue layers. The cells caught on the brush are smeared on a glass slide and then fixed with the provided alcohol-based fixative. The brush itself is placed in a vial of fixative and then both the slide and the brush are sent to the company for a computer-assisted specimen analysis. The brush biopsy cannot render a definitive diagnosis, but will give the practitioner more conclusive evidence of further abnormalities such as abnormal cells that have been detected. The results are classified as inadequate, negative, atypical or positive. An example for the use of such tests would be as a way to differentiate between white lesions caused by hyperkeratosis and those that are of a more serious nature. The test is also beneficial in persuading the patient that a biopsy is necessary since a patient may be reluctant to proceed directly to a scalpel biopsy. While false positives can occur, any positive result would warrant a surgical biopsy. Since false negative results can also occur negative results should be followed to ensure the lesions resolve. See OralCDx.com.