Contacts:

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

Carolyn Bumgardner Wang WeissComm Partners (415) 362-5018 x123 carolyn@weisscommpartners.com

DIADEXUS ANNOUNCES PRESENTATIONS HIGHLIGHTING THE ROLE OF Lp-PLA2 IN CARDIOVASCULAR DISEASE AND STROKE AT THE AMERICAN HEART ASSOCIATION SCIENTIFIC SESSIONS 2004

South San Francisco, CA - October 25, 2004 - diaDexus announced today multiple presentations highlighting the role of Lipoprotein-Associated Phospholipase A2 (Lp-PLA2), in vascular disease and vulnerable plaque. The presentations will take place at the American Heart Association (AHA) Scientific Sessions being held November 7-10, 2004 at the Ernest N. Morial Convention Center in New Orleans, LA.

The presentations are as follows:

Monday, November 8, 2004
Session Title: Inflammatory and Other Novel CVD Risk Factors
Oral Pres #3577: 9:15 a.m. - 9:30 a.m.

Association between Lipoprotein-Associated Phospholipase A2 and Coronary Artery Disease: Focus on its Relationship with Lipoproteins and Markers of Inflammation and Hemostasis

Tuesday, November 9, 2004
Session Title: Determinants of Plaque Rupture
Oral Pres #1183: 2:30 p.m. - 2:45 p.m.

Lipoprotein-Associated Phospholipase A2 is Highly Expressed in Macrophages of Coronary Lesions Prone to Rupture

Session Title: Advances in Cardiocerebrovascular Care and Stroke
Oral Pres #2979: 2:45 p.m. - 3:00 p.m.

Lipoprotein-Associated Phospholipase A2, High-Sensitivity C-Reactive Protein, and Risk for Ischemic Stroke in Middle-Aged Men and Women in the Atherosclerosis Risk in Communities Study

Session Title: Contemporary Issues in Dyslipidemia
Oral Pres #3786: 4:30 p.m. - 4:45 p.m.

The Effect of Statin Therapy on Lipoprotein Associated Phospholipase A2 Levels

Wednesday, November 10, 2004
Session Title: Inflammation and Adhesion
Poster Pres #1477: 9:00 a.m. - 5:00 p.m.

Biological Variability and Specificity of Lipoprotein-Associated Phospholipase A2, a Novel Marker of Cardiovascular Risk

About Lp-PLA2
Lp-PLA2 is an enzyme, primarily bound to LDL cholesterol, and has been found to be present in atherosclerotic plaque. The MONICA-Augsburg (MONItoring of trends and determinants in Cardiovascular disease) study, published in the October 2004 issue of Circulation, was the third study published in a peer-reviewed journal to show a statistically significant relationship between elevated Lp-PLA2 and the risk of a cardiac event in a large population. Among individuals in the MONICA-Augsburg population, a one standard deviation increase in Lp-PLA2 was associated with a 37% increase in the incidence of a coronary event.

About diaDexus
diaDexus, Inc., 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 for the quantitative determination of Lp-PLA2 in human plasma, 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.