Contacts:

Patrick Plewman diaDexus, Inc. (650) 246-6415

Carolyn Bumgardner Wang WeissComm Partners (415) 946-1065 office carolyn@weisscommpartners.com

DIADEXUS APPOINTS RICHARD B. LANMAN, M.D., TO EXECUTIVE TEAM

South San Francisco, CA - April 15, 2005 - diaDexus, Inc., a privately held biotechnology company, today announced the appointment of Richard B. Lanman, M.D., as executive vice president and chief medical officer.

"I am delighted to have Rick join diaDexus' executive management team and am confident that his extensive background in cardiodiagnostics and preventative care will prove invaluable to the company as we continue to build commercial support for the PLAC® test, our novel test for coronary heart disease," said Patrick Plewman, chief executive officer of diaDexus.

Dr. Lanman is an active national lecturer on the early detection and treatment of atherosclerosis and brings to diaDexus an extensive background in developing venture-backed healthcare services and technology companies. Prior to joining diaDexus, Dr. Lanman served as executive vice president, Corporate Business Development, and chief medical officer at Atherotech, a cardiodiagnostic company. Before joining Atherotech, Dr. Lanman was founder, chairman and chief executive officer of Adesso Healthcare Technology Services.

Prior to founding Adesso, Dr. Lanman served as senior vice president of Medical Operations and chief medical officer for San Jose Medical Management, which is responsible for 1,500 staff and network physicians.

Dr. Lanman earned a medical degree from Northwestern University Medical School and a bachelor's degree in chemistry from Stanford University, where he graduated Phi Beta Kappa.

About diaDexus
diaDexus, a privately held biotechnology company, based in South San Francisco, California, is focused on the discovery, development and commercialization of novel, patent-protected diagnostic and therapeutic products with high clinical value. The PLAC test, developed by diaDexus, is a blood test cleared by the U.S. Food and Drug Administration to aid in the prediction of an individual's risk for a coronary event, in conjunction with clinical evaluation and patient risk assessment. The PLAC test is currently available through laboratories nationwide. For more information about the PLAC test visit www.plactest.com. More information about the company may be found at www.diaDexus.com.