Contacts:

Patrick Plewman diaDexus, Inc. (650) 246-6400

Carolyn Bumgardner Wang WeissComm Partners (415) 225-5050 carolyn@weisscommpartners.com

DIADEXUS ANNOUNCES PRESENTATIONS HIGHLIGHTING ROLE OF Lp-PLA2 IN CARDIOVASCULAR DISEASE AND STROKE AT THE AHA SCIENTIFIC SESSIONS 2005

Company to Administer Free PLAC® Test to U.S.-based Attendees at Booth #4041

South San Francisco, CA - November 7, 2005 - DiaDexus announced today multiple presentations highlighting the role of the enzyme Lipoprotein-associated phospholipase A2 (Lp-PLA2) in cardiovascular disease and stroke. The presentations will take place at the American Heart Association (AHA) Scientific Sessions being held November 13-16, 2005 at the Dallas Convention Center in Dallas, Texas. The company will also administer the PLAC® Test for free to U.S.-based conference attendees who visit its booth (#4041). The PLAC Test measures an individual's levels of Lp-PLA2 (lipoprotein-associated phospholipase A2), and has been cleared by the FDA as an aid in risk assessment for a coronary event and ischemic stroke associated with atherosclerosis.

The presentations are as follows:

Sunday, November 13, 2005
Session Title: Traditional and Novel Risk Factors
Poster Pres #3596/P11: 9:00 a.m. - 5:00 p.m.

Association of Oral Contraceptive Intake and Different Hormone Replacement Therapies on Lipoprotein-associated Phospholipase A2 Plasma Concentrations in Apparently Healthy Women: MONICA Augsburg Study

Session Title: Traditional and Novel Risk Factors
Poster Pres #3601/P16: 9:00 a.m. - 5:00 p.m.

Sex and Age-Related Differences in Levels of Lipoprotein-Associated Phospholipase A2

Monday, November 14, 2005
Session Title: Acute Coronary Syndromes - Markers
Oral Pres: #1897: 9:30 a.m. - 9:45 a.m.

Lipoprotein-Associated Phospholipase A2 Additionally to NT-proBNP and Troponin I is Useful for Early Risk Stratification in Patients With Acute Coronary Syndrome: A Multimarker Approach

Session Title: Clinical and Experimental Aspects of Nutrition
Oral Pres: #3654: 11:00 a.m. - 11:15 a.m.

Lipoprotein-Associated Phospholipase A2 may Differentially Predict the Presence of Angiographic Coronary Artery Disease and Coronary Death across Glycemic Categories

About Lp-PLA2
Lp-PLA2 is an enzyme that is implicated in the vascular inflammatory pathway that leads to plaque formation and atherosclerosis. Previous hypotheses on the cause of coronary heart disease focused around lipid accumulation within the arterial walls. Increasing evidence now suggests that atherosclerosis is largely an inflammatory disease. Multiple published studies in peer-reviewed journals show a statistically significant relationship between elevated Lp-PLA2 and the risk of a major cardiovascular event.

About the PLAC Test
The PLAC test has been cleared by the FDA as an aid in predicting an individual's risk for a coronary event and ischemic stroke associated with atherosclerosis, in conjunction with clinical evaluation and patient risk assessment. The PLAC test is currently available through laboratories nationwide, including Quest Diagnostics Incorporated, Mayo Medical Laboratories, ARUP Laboratories and Berkeley HeartLab. For more information about the PLAC test, visit www.plactest.com.

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. More information about the company may be found at www.diaDexus.com.