The inactive X chromosome in a female cell is known as a barr body. This inactivation of the chromosome is caused due to the process of lyonization. The barr body is responsible for indicating the existence of the sex hormone. The buccal smear barr body test is performed to identify the inactive X-chromosome in the female cells and compare them with the male cells. It examines the cell structures. The test defines a barr body as round disk stuck to the nuclear membrane. This test is performed on a scrap of tissue collected from the lining of the mouth.