Product News: Bio-Rad Launches Test for Early Diagnosis of the Dengue Virus

19 Apr 2006

Bio-Rad Laboratories, Inc., a multinational manufacturer and distributor of life science research and clinical diagnostic products, announced today that it has introduced the Platelia Dengue NS1 Ag assay for dengue screening based on the specific detection of dengue virus NS1 antigen.

This fast and easy-to-use test provides early diagnosis of primary and secondary dengue acute infections.

By enabling diagnosis several days earlier than classic serological methods (detection of antibodies), the new test will help improve care for infected patients, reducing rates of mortality and morbidity. Bio-Rad is the first laboratory worldwide to introduce such a test to the market.

Earlier Detection of Dengue Viral Infection Needed
Dengue is a viral disease for which no specific treatment or vaccines are currently available, making early diagnosis critical to fighting against the disease.

Currently, routine tests used to screen the dengue viral infection are based on the detection of specific dengue virus antibodies. However, these particular antibodies are only produced several days after the first clinical signs appear—four to six days for a primary infection—which is insufficient for early screening.

The Platelia Dengue NS1 Ag assay, developed by Bio-Rad in partnership with the Pasteur Institute in France, is an ELISA test and enables the detection of NS1 dengue virus antigen as soon as the first clinical signs appear. The ability to detect the presence of the NS1 antigen offers earlier detection of the infection compared to the conventional serological methods that are currently used. The time saved is at least 6 days after a primary infection.

Test performance of the Platelia Dengue NS1 Ag assay has been confirmed through evaluations led by Bio-Rad teams as well as by reference laboratories of countries directly concerned by the disease, including Vietnam, Thailand, Singapore, India, Brazil and Guyana.

The sensitivity of the Platelia Dengue NS1 Ag assay has been shown to be 91% effective based on 177 retrospective sera from patients with current dengue infection confirmed by RT-PCR. Specificity was evaluated on 618 specimens including samples from 563 blood donors, 55 hospitalised patients and 200 potentially interfering sera. No positive results were observed in the test sample, providing 100% specificity.

In addition, Platelia Dengue NS1 Ag assay detects, with the same efficiency, all strains of the dengue virus. Early diagnosis, thanks to the detection of dengue virus NS1 antigen, will allow for considerable improvements in patient care. It will enable earlier suitable treatment to avoid serious complications and will help limit the spread of the disease.

Earlier Dengue Virus Diagnosis: a Major Public Health Issue
Dengue is a viral disease that has become dramatically more prevalent in the last few decades. Dengue is now endemic in more than 100 countries, mainly in tropical and subtropical regions.

The World Health Organisation estimates that 40% of the world’s population—some 2.5 billion people—are currently at risk from the disease, and between 50 to 100 million people are infected each year. The most severe form of the disease, dengue hemorrhagic fever, is also spreading, with 250,000 to 500,000 cases and 25,000 deaths each year, mainly among children under the age of 15.

Dengue is recognized internationally as a major public health issue. National governments and international health organisations have created programs to fight the disease in order to limit mortality and the socio-economical impact on local communities.

Produced and marketed by Bio-Rad, the Platelia Dengue NS1 Ag assay has been approved by the European Union (EC label). Local registrations are under discussion in several countries in South East Asia and Central and South America.