Researchers from the University Hospital of Copenhagen (Denmark) have developed a test that can detect HIV, hepatitis B and hepatitis C from a single drop of blood, which they have presented at the European Congress of Clinical Microbiology and Infectious Diseases (ECCMID) which is held in Copenhagen.
Hundreds of thousands of people die every year
More than a million people a year die from hepatitis B or hepatitis C. 650,000 people die each year from HIV-related causes and 1.5 million acquire the virus. The World Health Organization (WHO) has made eliminating the three viruses by 2030 one of its global health strategies, but new tests are needed if the number of cases is to be reduced.
The most common test for hepatitis B, hepatitis C, and HIV involves drawing a blood sample from a vein with a needle. Although this method works very well, there is a potentially large reservoir of all three diseases in places where this method is not suitable.
It can be about prisons, drug rehabilitation centers and homeless shelters, where venous blood sampling is not always adequate, or countries where shipping and refrigerated storage of blood samples can be difficult.
Analysis of dried blood spots
Other alternatives are dried blood spot testing, in which a single blood spot is tested for nucleic acid from all three viruses.
Stephen Nilsson-Moller and colleagues from the Department of Clinical Microbiology, University Hospital Copenhagene have validated evaluated one of these tests. To perform it, the person’s finger is pricked and some blood stains are collected on filter paper and allowed to dry.
Next, the Hologic Panther System analysis team uses a technique called transcription-mediated amplification to analyze one of the blood spots for genetic material from the three viruses. The assay is designed to, and normally is, performed on liquid plasma or serum samples, not the dry samples used here.
20 samples with known amounts of HIV, hepatitis B and hepatitis C were tested using the dried blood spot method (60 in total) and viruses were detected in all samples.
Plasma was also diluted to determine the lower limit of detection. This showed that it was possible to detect viruses at levels well below those normally found in untreated patients.
Nilsson-Moller points out that they have shown that, with existing hospital equipment, it is possible to detect HIV, hepatitis B and hepatitis C from a single drop of blood.
“The proof of dried bloodstain it is ideal for places where you do not want to use a needle for safety reasons or where it is less practical. For example, in prisons, drug rehabilitation centers and shelters for the homeless,” he explains. It is also suitable for developing countries or places where there is a risk that the blood sample will spoil before being transferred to a laboratory that can analyze it.”
“Blood samples should be tested in six hours if stored at room temperature, while dried blood spots can last for nine months without refrigeration,” he says.