Contacts:

Sharon Tetlow diaDexus, Inc. (650) 246-6400 stetlow@diadexus.com

Tama Antonia Donaldson Dorland Global Health (415) 262-5206

DIADEXUS WILL SUPPLY ANALYTE SPECIFIC REAGENTS

*FOR USE IN A TEST TO MEASURE Lp-PLA2 IN BLOOD

South San Francisco, CA - March 28, 2003 - diaDexus, Inc., a privately held biotechnology company based in South San Francisco, today announced it will be providing analyte specific reagents to Mayo Medical Laboratories. Mayo will use these reagents to develop a test for the quantitative measurement of lipoprotein-associated phospholipase A2 (Lp-PLA2) in blood.

Mayo Medical Laboratories is the international reference laboratory for Mayo Clinic. diaDexus is providing the analyte specific reagents for Mayo to offer an Lp-PLA2 test to its laboratory customers. Last year, diaDexus, Mayo Clinic and Mayo Medical Laboratories initiated a partnership to investigate potential clinical applications of an Lp-PLA2 test.

"Our collaboration with Mayo has allowed our teams to work together on exploratory studies to better understand the clinical applications of Lp-PLA2," said Patrick Plewman, chief executive officer of diaDexus.

In February 2003, diaDexus submitted a 510(k) pre-market notification to the U.S. Food and Drug Administration seeking marketing clearance for the PLAC™ test as an in vitro diagnostic product to be used as a predictor of risk for coronary heart disease.

About diaDexus
diaDexus, Inc., a privately held biotechnology company based in South San Francisco, Calif., is focused on the discovery, development, and commercialization of novel, patent-protected diagnostic and therapeutic products with high clinical value. diaDexus utilizes genomics and bioinformatics to identify disease-associated molecular targets. More information about the company may be found at www.diaDexus.com.

*Analyte Specific Reagent. Analytical and performance characteristics have not been established.

This information concerns a use that has not been approved or cleared by the Food and Drug Administration. The information is being disseminated at the expense of the manufacturer.