Diagnostic Tests

Newer, Improved HIV Tests Allow for Earlier HIV Detection

HIV tests have improved substantially over the years, and are now easier and less expensive, with a more rapid turnaround time for results.1

Three types of HIV tests are available:

  • Nucleic acid tests (NATs) — detects HIV ribonucleic acid (RNA)
  • Antigen/antibody combination tests — detects HIV p24 antigen as well as HIV immunoglobulin M (IgM) and immunoglobulin G (IgG) antibodies
  • Antibody tests — detects HIV IgM and/or IgG antibodies

Following an exposure that leads to HIV infection, the amount of time during which no existing diagnostic test is capable of detecting HIV is called the eclipse period.2

The time between potential HIV exposure and an accurate test result is referred to as the window period. Improvements in testing technology continue to reduce the detection window period, and, therefore, the time to diagnosis and treatment of early HIV infection. As seen in the figure, each type of HIV test has its own testing window, with the NAT capable of detecting HIV the earliest, followed by the antigen/antibody combination test, and lastly, the antibody test.

Figure indicating that each type of HIV test has its own testing window

Learn more about FDA-approved Tests for HIV.

  1. Branson BM, Owen SM, Wesolowski LG, et al. CDC. Laboratory Testing for the Diagnosis of HIV Infection: Updated Recommendations. https://dx.doi.org/10.15620/cdc.23447external icon. Accessed June 28, 2018.
  2. Hurt CB, Nelson JAE, Hightow-Weidman LB, Miller WC. Selecting an HIV test: a narrative review for clinicians and researchers. Sex Trans Dis 2017;44:739-746. PubMed abstractexternal icon.