CK20 HIS stands for Cytokeratin 20 Immunohistochemistry. CK20 test is carried on to check the level of CK20 in the Biopsy Tissue. This test helps to identify if a patient is diagnosed with Bladder Cancer and Tumors of Lower GI tract. Doctors may suggest this test during the treatment and after the treatment of Bladder Cancer and Tumors of Lower GI Tract.