Diagnostic Products Corporation Cooperating with FDA Regarding the FDA's Application Integrity Policy

LOS ANGELES March 3, 2004—Diagnostic Products Corporation (NYSE:DP) reported that in response to a letter from the U. S. Food and Drug Administration (FDA), it is cooperating with the FDA to address and resolve issues raised by the FDA's decision that the FDA's Application Integrity Policy should be applied to Diagnostic Products Corporation (DPC). The letter stated that this action was taken based on the FDA's inspectional findings related to DPC's Chagas diagnostic test application. In its letter the FDA stated that it suspended review of the pending diagnostic test applications DPC has submitted and will also defer scientific review of any future submissions until these issues are resolved.

"We have initiated a process to identify and correct the causes of these issues," stated Michael Ziering, CEO of Diagnostic Products, "Our understanding is that a reasonable time for the resolution of these types of issues is approximately 12 months. Our new instrument, the Immulite 2500, and 74 assays which run on it have already been cleared by the FDA." This action by the FDA also does not affect the introduction of tests that are sold into international markets, which in 2003 accounted for 71% of the company's sales.

Founded in 1971, Diagnostic Products Corporation (DPC) is the global leader dedicated exclusively to immunodiagnostic testing. The Company's product menu includes over 400 tests to measure microorganisms, hormones, drugs and other medically important substances present at infinitesimal concentrations in body fluids and tissues. DPC also designs and manufactures automated laboratory instrumentation which provides fast, accurate results while reducing labor and reagent costs. DPC sells its products to hospitals, clinics and laboratories domestically and in over 100 international countries. Additional Company information can be found on the Company's web site at www.dpcweb.com.

Except for the historical information contained herein, this press release contains forward- looking statements that involve risks and uncertainties that could cause actual results to differ materially. These factors include the effects of governmental or other actions relating to the FDA action reported herein or relating to actions by DPC's Chinese subsidiary; the rate of customer demand for the Company's products; the Company's ability to successfully market new and existing products; its dependence on certain suppliers; its ability to keep abreast of technological innovations and to translate them into new products; competition; political and economic instability in certain foreign markets including the movements in foreign currencies relative to the dollar; and other risks and uncertainties disclosed from time to time in the Company's SEC reports and filings.