Calypte Receives FDA Approvals on Revised Labeling for Urine Screening and Supplemental Tests; Provides Opportunity for Increased Marketing Opportunities.

Business Editors/Health/Medical Writers

ALAMEDA, Calif.--(BUSINESS WIRE)--May 23, 2003

Calypte Biomedical Corporation (OTCBB:CALY), the developer and marketer of the only two FDA approved HIV-1 antibody tests that can be used on urine samples, as well as an FDA approved serum HIV-1 antibody Western blot supplemental test, announced that it has received several recent FDA approvals for revisions to the product labeling for its Calypte HIV-1 Urine EIA screening test and its Cambridge Biotech HIV-1 Urine Western Blot supplemental test. These two products are used in the current FDA-accepted HIV testing algorithm where a reactive screening test result is followed up with a supplemental assay for confirmation of the screening result.

"When the HIV-1 Urine EIA screening test was approved by FDA in 1996, there was no approved urine supplemental test," said Don Kafader, Calypte Biomedical's Director of Regulatory Affairs. "As a result, certain limitations were noted in the product's package insert. Many of these limitations remained in place after the subsequent 1998 FDA approval allowing urine samples to be tested with the Cambridge Biotech HIV-1 Western Blot.

"Now that urine HIV testing has been around for several years, the medical and laboratory professions and the FDA are more comfortable with the technology and with the performance of the overall urine testing algorithm. These recent FDA approvals now allow us to remove many of the limitations and restrictions imposed at the time of the original approvals."

The company is currently in the process of implementing the new product package inserts, the Subject Information Brochure and other associated labeling materials. "We believe that the FDA's action is very significant in that it should facilitate our ability to market our tests to clinics and testing centers throughout the U.S.," stated Nancy Katz, Calypte's President and Chief Executive Officer. "It has been one of our continuing goals to provide products that allow more people to be tested in easier, less painful ways. FDA's recent approvals to revise our product labeling to encourage broader use of our products facilitates our ability to accomplish this critical goal."

About Calypte Biomedical:

Calypte Biomedical Corporation, headquartered in Alameda, California, is a public healthcare company dedicated to the development and commercialization of urine-based diagnostic products and services for Human Immunodeficiency Virus Type 1 (HIV-1), sexually transmitted diseases and other infectious diseases. Calypte's tests include the screening EIA and supplemental Western Blot tests, the only two FDA-approved HIV-1 antibody tests that can be used on urine samples. The company believes that accurate, non-invasive urine-based testing methods for HIV and other infectious diseases may make important contributions to public health by helping to foster an environment in which testing may be done safely, economically, and painlessly. Calypte markets its products in countries worldwide through international distributors and strategic partners. Current product labeling including specific product performance claims can be found at www.calypte.com.

Statements in this press release that are not historical facts are forward-looking statements, including statements regarding announcements of financial results and presentations by the Company. Such statements reflect management's current views, are based on certain assumptions and involve risks and uncertainties. Actual results, events, or performance may differ materially from the above forward-looking statements due to a number of important factors, and will be dependent upon a variety of factors, including, but not limited to, our ability to obtain additional financing that will allow us to continue our current and future operations and whether demand for our product and testing service in domestic and international markets will continue to expand. The Company undertakes no obligation to publicly update these forward-looking statements to reflect events or circumstances that occur after the date hereof or to reflect any change in the Company's expectations with regard to these forward-looking statements or the occurrence of unanticipated events. Factors that may impact the Company's success are more fully disclosed in the Company's most recent public filings with the U.S. Securities and Exchange Commission ("SEC"), including its annual report on Form 10-K for the year ended December 31, 2002 and its subsequent filings with the SEC.