Description

The HIV-1/2 Antigen and Antibodies Test, also called a 4th generation HIV test, is designed to detect both HIV-1/HIV-2 antibodies and HIV-1 p24 antigen. This allows for earlier detection of HIV infection, including primary HIV-1 infection, compared to earlier generation tests.

Purpose of the Test

  • Aid in diagnosing HIV-1 and HIV-2 infections
  • Detect recent (acute) HIV-1 infection via p24 antigen
  • Identify immune response to HIV through antibodies
  • Provide early information to guide treatment and counseling

How the Test Works

  • A blood sample is collected via venipuncture
  • The test detects:
  • HIV-1 p24 antigen: Appears in the blood within 2–4 weeks after infection
  • HIV-1 and HIV-2 antibodies: Produced by the immune system 3–12 weeks after infection
  • Combining antigen and antibody detection shortens the window period for accurate diagnosis

When to Order

  • As routine screening, recommended at least once for all adults
  • Following potential HIV exposure (sexual contact, shared needles)
  • For pregnant individuals to prevent perinatal transmission
  • To confirm infection in symptomatic individuals

Interpretation of Results

  • Positive result: Indicates current or past infection; requires confirmatory testing
  • Negative result: Likely no infection, though very recent exposures may not yet be detectable
  • Early detection via p24 antigen allows intervention before antibodies are fully developed

Note: HIV is manageable with antiretroviral therapy but currently not curable. Early diagnosis and treatment are crucial to maintain immune function and prevent progression to AIDS.

Fasting not required.