A method for determining the adequacy of a cervical or urethral test specimen collected for a chemical assay to detect the presence of Chlamydia trachomatis . Cells present in the specimen are disrupted to expose a substance present in or on C. trachomatis that is detectable by chemical reaction. In order to determine if the test specimen contains an adequate amount of the cervical or urethral cell type that serves as the host cell for C. trachomatis , the disrupted specimen is also reacted with a chemical reagent that produces a detectable response upon reaction with a substance present in or on columnar epithelial cells. The present invention therefore provides a control reaction that verifies the adequacy of the collected test specimen and thereby increases the confidence that a negative test result for the presence of Chlamydia indicates the absence of a C. trachomatis infection in the patient.