High Quality Content by WIKIPEDIA articles! The antigen leukocyte cellular antibody test (ALCAT) is a procedure created by American Medical Testing Laboratories and now marketed by Cell Science Systems, of Deerfield Beach, Florida, also known as ALCAT Diagnostic Systems. They marketed the procedure as an in-vitro screening test for adverse reactions to specific foods, food additives, food colourings and other chemicals, between 1984 and 1986. Since this time the original test method has been modified.