Understanding Primary vs. Confirmatory Types of HIV Tests

September 18, 2018

Testing for HIV is done in two phases. First, there is a main test finished. When it’s favorable, then the test is repeated to check for false positives. In the event the primary evaluation is positive double, then the sample is tested with another, more specific confirmatory test. This test can be used to make sure the primary test isn’t responding to a disease aside from HIV.

How HIV Test Types Are Used in Combination

There are a number of ways that you can consider the types of HIV tests.

One way is to consider the ways the various test types operate. The other way is to look at the way the different kinds of HIV tests are utilized. Main tests are utilized to try to find any sign of HIV. Confirmatory tests are used to look at the outcomes of tests that were primary. The goal of the process is to minimize the danger of incorrectly diagnosing anyone.

Tests Used for HIV Main Testing

  • EIA or Enzyme Immune Assay: This test looks for antibodies to HIV. But it has its limitations. Many men and women start producing anti-HIV antibodies within 6-12 weeks of infection. However, some HIV positive people are able to take up to 6 months to produce enough antibodies to test positive on an EIA test. Therefore this test is not helpful for recently infected individuals. With this evaluation, someone recently infected with HIV might not test positive. But, they can still pass HIV onto other men and women. They may, in fact, be very infectious.
  • ELISA or Enzyme-Linked Immunosorbent Assay: This evaluation is similar to an EIA. It uses different techniques and components, although it seems for exactly the very same items.
  • PCR or Polymerase Chain Reaction: This test employs technology to amplify viral RNA from the blood. In other words, it makes copies of RNA. This permits the RNA to be more easily found. Therefore, PCR will help detect small quantities of virus in a person. However, it’s pricey, time-consuming, rather than readily available

    Tests employed for HIV Confirmation

    • Western Blot: This is the main method used to confirm that the results of a first positive test. It’s an antibody test that is more specific for HIV-antibodies compared to EIA/ELISA tests. But, it is more expensive. That’s why it’s used for confirmation instead of testing.
    • RIPA: This blood test is completed when antibody levels are reduced. In addition, it can be achieved when Western Blot results are unclear. This evaluation is expensive, hard to execute and not frequently used.
    • Immunofluorescence Assay. This is another type of confirmatory test utilized when Western Blot results are unclear. At times it is used instead of a Western Blot.
    • DNA/RNA Amplification Tests: These evaluations are similar to PCR. They are sometimes used when the consequence of a western blot remains cloudy. Amplification tests are now much less expensive over time.

    Tests can also be employed to determine a person’s viral load. This is the amount of virus present in their bloodstream. Viral load tests are not utilized to diagnose HIV. These evaluations are utilized to track how successful treatment is. However, there is some research that suggests that assessing viral load in the exact same time as HIV is diagnosed may help connect people to a doctor for care.​