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Acute and Rapid HIV Testing

Most individuals who are infected with HIV develop antibodies within three months of being infected.  The two most common tests for HIV, the Western Blot (WB) and immunofluorescent assay (IFA), confirm HIV by testing for the presence of such antibodies. The rapid HIV tests, such as the Reveal HIV-1 Antibody Test and OraQuick Rapid HIV-1 Antibody Test, can use various specimens (saliva, blood finger stick, urine) to check for antibodies.

Acute HIV test

Since it may take as along as three months before antibodies are present, some individuals with HIV may receive a “false negative” test result because their body has not yet started making antibodies.  Routine HIV antibody tests produce a false negative for many during four to five weeks after infection.  For this reason the Nucleic Acid Amplification Test (NAAT) was created.  It can detect the HIV virus as early as two weeks after infection.

A 2005 study published by the New England Journal of Medicine (NEJM) focused on the capabilities of the NAAT.  North Carolina added the test to its standard HIV antibody tests to detect individuals with acute HIV (those who did not yet have antibodies).  The study found that the NAAT “significantly increases the identification of cases of infection.”  When used with traditional immunoassays, NAAT “increased the number of incident cases available for the estimation of incidence of HIV infection by 21 percent.”

The study found a cost of $402,861, or 3.3 percent increase, in the annual budget of $12,053,465 dedicated to HIV services.  This is a cost of $3.63 per specimen.

Antibody tests alone can detect 96 percent of HIV infections (NEJM). Another study found that 92 percent of HIV infections were found by antibody tests (JAMA).  Thus, between 4-8 percent of people with HIV will receive a “false negative” result.  Early diagnosis is important for three reasons.  First, clinical treatment can begin earlier, possibly delaying the progression of the disease.  This will increase the number of HIV diagnoses and do so sooner than traditional antibody tests. Secondly, further transmission of HIV can be prevented.  It has been found that “the probability of transmission is high during the first few months after acute HIV infection,” so preventing transmission is crucial.  The third reason early diagnosis is important is because it can improve HIV surveillance.  The CDC has been working to distinguish recent from past HIV infections, and this test can pinpoint recent infections.  This is important for monitoring trends, populations, and risk factors.

The study concluded by saying “We believe that the work that has been done to date with nucleic acid amplification testing for HIV is now sufficient to allow us to conclude that this form of testing should be a standard tool for the prevention and surveillance of HIV infection and for the care of infected persons.”

The Texas Department of State Health Services put forward a report on emerging technologies in HIV testing.  They say, “It is estimated that over half of new sexually transmitted HIV infections are due to people unaware of their infection.  Evidence indicates that once individuals become aware of their serostatus, they reduce risky behaviors and decrease HIV transmission.”  The report praises the sensitivity of the NAAT for acute HIV infections.

Rapid HIV test

Future HIV testing may include the improvement of rapid urine tests and the development of NAAT for oral fluids and blood finger sticks.  “Rapid NAATs have the potential to revolutionize HIV testing by offering sensitive tests that can identify HIV a week after infection” (DSHS).

During 2004- 2006, the CDC provided a program with rapid HIV tests in targeted minority communities.  A report published in The Journal of the American Medical Association (JAMA) found that rapid HIV testing “in outreach and other community settings can identify large numbers of person in racial/ethnic minority populations and others at high risk who are unaware they are infected with HIV.”  The program used Oraquick Rapid HIV-1 Antibody Test on either oral fluid or whole blood specimens, and results were available 20-40 minutes after specimen collection.

Another study published by JAMA focused on voluntary rapid HIV testing in emergency departments (EDs).  It proposes that EDs “consider integrating rapid HIV testing into their routine medical services to identify patients who are unaware that they are infected with HIV and link them to health services.”  Individuals in the study who were found to be HIV positive were given “HIV risk-reduction information, partner counseling and referral services, and medical care appointments.”

The study proposes that HIV testing be a part of routine services in the EDs, rather than on a risk-based approach.  Over half (56.5%) of the individuals offered a HIV test agreed to be tested, “indicating that opt-in testing is acceptable in ED settings.”  However if a risk-based approach had been taken, 48% of individuals with the newly diagnosed HIV infection would not have been offered testing.