What are the steps for diagnosing and treating Human Immunodeficiency Virus (HIV) infection?

HIV Diagnosis and Treatment Protocol

HIV infection should be diagnosed using a sensitive screening test such as enzyme-linked immunosorbent assay (ELISA) or rapid assay, followed by confirmation with Western blot or indirect immunofluorescence assay (IFA) to ensure accurate diagnosis and prompt treatment initiation. 1

Diagnostic Testing Algorithm

Initial Screening

• Begin with a sensitive screening test - either ELISA or rapid HIV test 1
• Obtain informed consent before performing HIV testing 1
• For rapid testing in resource-limited settings, tests like SD Bioline HIV 1/2, Determine HIV-1/2, or Uni-Gold HIV-1/2 have demonstrated high sensitivity (97.7-100%) 2

Confirmatory Testing

• All reactive screening tests must be confirmed by Western blot or indirect immunofluorescence assay (IFA) before being considered definitive 1
• If confirmatory testing results are negative or indeterminate, follow-up testing should be performed on a blood specimen collected 4 weeks after the initial reactive test 1
• Be aware that antibody tests cannot rule out infection that occurred less than 6 months before the test, as HIV antibody is detectable in ≥95% of patients within 6 months of infection 1

Special Considerations

• For infants <15 months born to HIV-positive mothers, definitive diagnosis should be based on laboratory evidence of HIV in blood or tissues by culture, nucleic acid, or antigen detection (not antibody testing alone) due to transplacental passage of maternal antibodies 1
• Consider HIV-2 testing in persons from endemic regions (West Africa, Angola, Mozambique, Portugal, France) or their sexual partners 1
• Test for HIV-2 when there is clinical evidence of HIV disease but negative HIV-1 antibody tests 1

Post-Diagnosis Protocol

Medical Evaluation

• All persons with positive HIV tests must receive comprehensive medical evaluation or be referred for these services 1
• Early intervention is critical even for asymptomatic patients, as persons newly diagnosed may be at different stages of infection 1
• Monitor immune function through CD4 count and viral load testing to determine disease progression and treatment needs 1

Treatment Initiation

• Begin antiretroviral therapy with FDA-approved medications such as:
  • Protease inhibitors (e.g., darunavir) co-administered with ritonavir and other antiretroviral agents 3
  • Integrase strand transfer inhibitors (e.g., dolutegravir) in combination with other antiretroviral agents 4
• For treatment-experienced patients, conduct genotypic and/or phenotypic testing prior to therapy initiation to assess drug susceptibility 3
• Monitor liver function before and during therapy, particularly with protease inhibitors 3

Psychosocial Support

• Provide behavioral and psychosocial services as an integral part of HIV care 1
• Address emotional distress at diagnosis, when notified of changes in immunologic markers, when therapy is initiated, and when symptoms develop 1
• Help patients navigate challenges including:
  • Accepting potential life implications
  • Coping with stigma
  • Developing strategies for maintaining physical and emotional health
  • Initiating behavioral changes to prevent HIV transmission 1

Common Pitfalls and Caveats

• Rapid tests may have lower specificity compared to ELISA; reactive results should be confirmed with Western blot for definitive diagnosis 5
• False-negative results can occur during the "window period" (recent infection within 6 months) 1
• Some ELISA kits show variable performance - choose validated kits with high sensitivity and specificity 6
• Avoid relying solely on rapid tests in high-stakes settings like blood banks where ELISA remains the preferred screening method 6
• Never disclose a positive HIV diagnosis without confirmatory testing, as false positives can occur with screening tests 1