Four Cases of HIV Transmission May Dictate Use of the Nucleic Acid Amplification Test

The Tribune reported yesterday that four transplant recipients in Chicago have contracted HIV and hepatitis C from an organ donor. It is the first time in more than a decade that HIV was spread by organ transplants and the first reported instance in which both viruses were spread by the same transplant.

The error highlights a significant gap in transplant testing. Current diagnostic methods do not test for the virus itself, but rather detect antibodies produced by the immune system in response to the infection. Using these antibody based diagnostics, it can take as long as 22 days for HIV (and 82 days for hepatitis C) to be detected after initial exposure.

The news struck an industry which is only just recovering from the gruesome tale of stolen body parts, contaminated tissue and slackened testing brought on by the irresponsible behavior of Biomedical Tissue Services (BTS), which allegedly attained body parts without donor permission.

Although the risk of the disease transmission which occurred in Chicago is extremely unlikely (since 1994 some 300,000 transplants have occurred without HIV transmission) the latest scandal may cause a new series of CDC regulatory revisions which stipulate the use of more rigorous diagnostic testing.

The nucleic acid amplification test, or Naat, detects the presence of infection by directly testing for viral genomic nucleic acids rather than by indirectly testing for the presence of antibodies. Use of this technique provides a much higher level of sensitivity and specificity than routine testing methods currently provide. If such a test were used in Chicago, it is likely that the HIV transmission would have been avoided.

The National Institute of Health began using the Naat as an investigational screening method for donated blood in mid-1999. Science Daily reports the test has helped prevent the transmission of approximately five HIV-1 infections and 56 hepatitis C virus infections each year since its U.S. introduction. The Naat system was approved by the FDA is 2002.

Blood, however, is more ‘shelf-stable’ than organs. Naat is more time-consuming than other tests – and time is an issue as organs begin to deteriorate soon after donor death. Another concern is the increased likelihood of false-positives – as hospitals continue to grapple with an already tenuous supply of donor organs.

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