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Blood Spot on a Card: the Cheaper, Easier Way to Test Infants for HIV

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A new way to collect blood samples from infants has the potential to help doctors diagnose HIV much earlier, while also cutting costs. The method could also help reduce the number of HIV-infected children requiring long term treatment.

The technique could prove most valuable in regions where rates of HIV are high and access to medical facilities is limited. Sub-Saharan Africa is one of these regions. In 2010, 22.9 million people were HIV positive. 59% of people living with HIV were women. In 2010, 3.4 million children under the age of 15 were living with HIV globally, more than 90% were living in sub-Saharan Africa.1

The test is essentially a small card containing a cotton cellulose paper collection pad. The card is imprinted with a blood spot and wrapped for protection before being sent off for testing.

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These cards can be used for HIV testing mainly for infants at risk of mother to child transmission of HIV infection during pregnancy, birth, or breastfeeding. When used for HIV infant diagnosis, a small volume of blood from an infant’s heel is applied to the sample collection area and then allowed to dry out. The card, complete with the dry dried blood spot, is then packaged for transport to a test laboratory.

This method of collecting samples has been shown to lower the cost of consumables by up to 40% in comparison to serum or plasma collection. A heel prick or finger stick sample avoids the use of needles and syringes and involves minimal sample manipulation with no further sample processing in the field required.

The convenience and stability of the samples collected this way could well pave the way for more screening to be carried out in this way. Current methods of testing HIV-exposed infants involve the use of an HIV nucleic acid test at 4 to 6 weeks of age.

Since infants retain maternal antibodies for up to 12 to 18 months after birth, low cost enzyme-linked immunosorbent assay (ELISA) antibody HIV tests cannot distinguish maternal and infant antibodies, thus being unable to provide a definitive diagnosis.

Nucleic acid polymerase chain reaction (PCR) testing at six weeks has been found to be more useful in identifying HIV than ELISA. However, a number of challenges make it often inaccessible (e.g. infrastructure, logistics, lab facilities, resources, skills required for sample collection and testing, cost of PCR test kits).

The cards have been used by former U.S President Bill Clinton’s HIV/AIDS Initiative (CHAI) for the collection of blood samples for early HIV/AIDS detection in infants in connection with CHAI’s Pediatric Initiative.

The initiative, which began back in 2008, focused on access to ART and prevention of mother-to-child transmission. CHAI assists countries by implementing large-scale, integrated care and treatment programs. It partners with 22 countries in Africa, the Caribbean, Asia, and Eastern Europe.

The donation of these cards has allowed CHAI to reach more children in developing nations in order to identify those children at risk for HIV/AIDS infection. With early detection these children can be treated with the life-saving medications they need to combat infection.

 

References

1WHO Progress Reports: Global HIV/AIDS Response: Epidemic update and health sector progress towards Universal Access (2008-2011)

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