Pinoy scientists invent 'pregnancy test' for dengue

Monday, August 05, 2013 05:37 AM    Views : 496by:KIM LUCES,GMA News
It's like a pregnancy test, only for dengue: just place a few drops of blood into a plastic wand, and see if you're positive after 15 minutes.
 
Like in your ordinary off-the-shelf pregnancy test, a strip of specially-treated materials soaks up the fluid and changes color in the presence of specific chemicals.
 
A product of a study by the Research and Biotechnology Division of the St. Luke's Medical Center with the help of the Department of Science and Technology (DOST), this approach is being developed as a "point-of-care" test for dengue meant to be simple enough to be done even by people without medical training.  
 
Shrugging off dengue: fatal
 
The problem with dengue is that its most common symptom—fever—is usually shrugged off by sufferers, delaying medical attention. It's only when the fever persists for three or four days that people decide to consult a doctor. But by then, the dengue will already have progressed so time is of the essence, Dinamay said.

"Dengue should not be a fatal disease," said Dr. Mark Pierre Dimamay, a member of the research team. It only becomes deadly when treated too late or not treated at all.

While it is too early to tell how much this device might cost, the team is hoping that it is "around the cost of a pregnancy test since they are similar in format."

A prototype of the product has already been produced, with field testing scheduled for next year.
 
How it works
 
The dengue test prototype is designed to detect dengue even in its earliest stages, well before the breakout of any tell-tale fever. 
 
The test involves two strips: one that detects the dengue virus itself in the earlier stages of contamination, and another that reacts to the antibodies produced after virus numbers have subsided. 
 
This is because, once the dengue virus enters a person, it multiplies until it reaches a peak level; this is when the symptoms, like fever, start to manifest. But after the fourth day of contamination, virus numbers drop as the body counterattacks by producing antibodies.
 
So the test works by detecting both the virus and the antibodies produced in its wake.
 
Other existing methods
 
A similar device called the Rapid Dengue Test is already available in the market. Unlike the point-of-care prototype of the St. Luke's team, it only detects the antibodies against dengue, which appear in the blood four to five days after the onset of fever.
 
Yet another device called the Dengue NS1 Ag Strip is being used by some hospitals to test early dengue infection. However, it still won't fit the ideal point-of-care test, Dimamay said, because its end-users are still healthcare professionals: "The patients cannot perform this test by themselves," he explained.
 
Methods for diagnosing dengue like the Nucleic Acid Amplification, serological methods, and virus isolations require technical expertise and a lot of time, which don't make them ideal point-of-care screening tools for general fevers.
 
These methods need a laboratory and specialized equipment, plus the technical expertise of the people performing the tests. These methods would also take at least half a day to finish, Dimamay said. — TJD, GMA News

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