LABORATORY CORPORATION OF AMERICA HOLDINGS LIST OF SUBSIDIARIES Laboratory Corporation of America a Delaware company Executive Tower Travel Inc. a Delaware company Tower Collection Center, Inc. a Delaware company National Laboratory Center Inc. d/b/a/ MedExpress a Tennessee company CompuChem Corporation a Massachusetts company CompuChem Laboratories, Inc. a Delaware company ChemWest Analytical Laboratories, Inc. a Delaware company LabCorp Limited a United Kingdom company Lab Delivery Service of New York City, Inc. a New York company