New test can identify past viruses with just one drop of blood

Scientists in the US have claimed that a new test can reveal every virus a person has ever had, just by using one drop of their blood.

The new blood test, which costs as little as $25 (€22), is reportedly able to detect over 1,000 strains of the 206 different types of viruses which are known to infect humans from just one drop of a patient's blood. It works by detecting the existing antibodies within a person's immune system that were created in the past to tackle viruses and have remained in the system in case the virus returns.

The trials for the test were carried out on 569 people from the United States, South Africa, Peru and Thailand. The results from their individual blood samples, published yesterday in a report in the journal Science, showed that most people had been exposed to about 10 different kinds of virus over their lifespan, most commonly the common colds and flus.

Dr Stephen J. Elledge, the senior author of the report, and a professor at Harvard Medical School, told the New York Times that the results of the trials surprised scientists carrying out the research. He explained that they found that the immune response is very similar from person to person, refuting scientists' previous beliefs that each person's individual immune system responded with different antibodies to the same types of virus.

Elledge said that whilst the new method, named "VirScan", represents a "large step forward toward the goal of comprehensive analysis of viral infections" there are unfortunately some limitations to the tests.

Although it gave accurate results, including for those who had the HIV and Hepatitis C viruses, Elledge highlighted to the New York Times that the test "can miss certain very small viruses or past infections to which the immune response has dwindled." He added that researchers hope to develop newer versions of the test which will be even more sensitive.

It currently takes between two days to two months for the results of the test to come through. The research is funded by the Howard Hughes Medical Institute but Elledge told the New York Times that with more money, they'd be able to streamline the process so that the turnaround time for results was always two or three days.

"We don't have a company," he said. "We haven't started one or even taken the first step. It should go to a company, though. That's what can make it work for people."

The test costs around $25 to perform and there are hopes it will radically improve the scientific understanding of chronic diseases which in turn may lead to developing more effective vaccines.