N.C. Researchers Find Cost-Effective Way of Conducting HIV Test That Detects Virus Earlier, Could Reduce Spread of Disease
Researchers at the University of North Carolina-Chapel Hill in collaboration with the North Carolina Division of Public Health on Wednesday announced they have found a cost-effective way to use an improved but expensive HIV test that can detect the virus weeks earlier than standard screening, the Raleigh News & Observer reports. The study -- which was funded by NIH and used donated lab supplies -- was published in the May 5 issue of the New England Journal of Medicine. Christopher Pilcher, an associate professor of medicine at UNC-CH, and colleagues tested 109,250 patients between November 2002 and October 2003 at state-funded testing sites. The researchers found 583 HIV-positive people using standard HIV antibody testing but identified an additional 23 cases when they used the "more sophisticated" nucleic acid amplification to test the negative samples, according to the News & Observer (Avery, Raleigh News & Observer, 5/5). Nucleic acid testing, which was developed in 1999, is used to screen about 14 million units of donated blood each year. NAT can detect minute amounts of viral genetic material in pooled plasma samples by amplifying gene fragments of the virus. If a pool tests positive for HIV, the individual sample can be detected and removed for further processing, and the donor can be deferred and notified (Kaiser Daily HIV/AIDS Report, 8/19/04). Because NAT looks for the virus and not antibodies, health professionals are able to identify HIV-positive patients in the days immediately following infection -- when they are most contagious -- which could help slow the spread of virus. Following interviews with the 23 patients who were newly infected, researchers and public health workers identified 18 more HIV-positive people who were sex partners of the people identified through the study (Raleigh News & Observer, 5/5). Testing with the more sophisticated method produced two false positive results, according to the study.
Although NAT is used regularly to track the progression of HIV in patients, the high cost of the test has prohibited its use for initially screening patients for the virus, Reuters reports. Standard screening costs less than $10 per test, compared with about $60 for NAT. However, the UNC-CH researchers found that testing batches of about 90 samples of blood would add $3.63 to the cost of testing each person (Emery, Reuters, 5/4). Finding ways to reduce the cost of NAT screening was "one of the major objectives" of the study, the News & Observer reports. North Carolina is the only state that routinely uses NAT to screen people for HIV infection, according to Dr. Peter Leone, a study author and the medical director of the HIV/STD Prevention & Care branch of the state Department of Health and Human Services. Leone said that identifying HIV-positive people early and preventing the further spread of the disease -- as well as preventing mother-to-child HIV transmission in some cases -- saves the state money in treatment and care costs, according to the News & Observer.
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"This tool will provide an opportunity for us to fight the epidemic in real time," state Health Director Dr. Leah Devlin said, adding, "We can go from a point of testing to follow-up care to treatment within 48 hours. That's a lot of energy, but I'm telling you, that's going to save lives" (Raleigh News & Observer, 5/5). Pilcher said other states might be "slow to adopt" the new testing strategy because it requires "a new mind-set for laboratories," according to Reuters. "There are two decades of tradition on how HIV testing should be performed," he said, adding, "What we're really recommending is turning the paradigm around, where the role of the laboratory is not to do antibody screening and confirm the positive, but do antibody screen and then confirm the negative" (Reuters, 5/4). Dr. John Bartlett, an AIDS researcher and clinician at Duke University Medical Center, said NAT could help health professionals track the spread of HIV by tracing the sexual partners of people who test positive. "I think it's a useful tool, but whether it translates in any change in ongoing HIV infections remains to be seen," he said. The researchers said they would continue to gather data on NAT and study whether antiretroviral treatment is more effective in the earliest days of HIV infection, the News & Observer reports (Raleigh News & Observer, 5/5).