What are the next steps after a positive Human Immunodeficiency Virus (HIV) screening test with negative HIV antibodies?

From the Guidelines

If you have a positive HIV screening test but negative HIV antibodies, you should undergo additional confirmatory testing, specifically an HIV RNA viral load test, as soon as possible to determine the presence of HIV infection. This discrepancy could indicate either a false positive screening test or an early HIV infection (acute HIV) where antibodies haven't yet developed 1. Contact your healthcare provider immediately to arrange this follow-up testing. While waiting for results, avoid sexual contact or use barrier protection to prevent potential transmission. Don't assume the negative antibody test means you're HIV-negative, as early infection can be highly contagious despite negative antibody tests. This situation occurs because during early HIV infection, the virus is present and detectable by RNA testing, but the body hasn't yet produced enough antibodies to be detected by antibody tests. This "window period" typically lasts 2-8 weeks after infection.

Key Considerations

• The initial step after a positive screening test is to confirm the diagnosis with a more specific test, such as the Western blot assay or indirect immunofluorescence assay (IFA) 1.
• However, in cases where HIV antibodies are negative, an HIV RNA viral load test is recommended to detect early infection 1.
• It's crucial to follow up with a healthcare provider for guidance on additional testing and prevention measures.
• Repeat antibody testing in 2-4 weeks may be recommended regardless of the RNA test results to ensure accuracy.

Prevention and Next Steps

• Avoid sexual contact or use barrier protection to prevent potential transmission while waiting for confirmatory test results.
• If confirmed to be HIV-positive, discuss treatment options with a healthcare provider, considering the latest guidelines for antiretroviral therapy.
• For individuals with recent exposure, post-exposure prophylaxis (PEP) may be considered, as outlined in guidelines for the use of antiretroviral agents in HIV-infected adults and adolescents 1.

From the Research

Next Steps After a Positive HIV Screening Test with Negative HIV Antibodies

• If a patient receives a positive HIV screening test result but has negative HIV antibodies, the next steps may involve further testing to confirm the diagnosis, as false-positive results can occur 2.
• In cases where the screening test is positive but the confirmatory antibody test is negative, plasma HIV RNA assays may be used to detect acute HIV infection 3.
• Qualitative human immunodeficiency virus type 1 nucleic acid amplification tests (HIV-1 NATs) can be used as adjunct confirmatory tests for HIV antigen (Ag)-positive specimens and for patients with indeterminate or negative HIV antibody (Ab) confirmatory test results 4.
• Patients with newly acquired HIV may not have a reactive screening result, and repeat testing may be necessary to confirm the diagnosis 5.
• Clinicians should be aware of the potential for false-positive HIV test results in patients who recently received vaccination or have other immune triggers, and retest at a short interval if suspected 2.

Considerations for Acute HIV Infection

• Acute HIV infection may present with symptoms such as sore throat, odynophagia, and back and flank pain, but patients may not have a reactive screening result 5.
• The p24 seroconversion window, during which the patient may have a negative screening result, should be considered when interpreting test results 5.
• Emergency department providers should be aware of the potential for atypical HIV results and consider further testing to rule out HIV infection 5.

Laboratory Testing

• Fourth-generation rapid screening tests combining HIV-specific antibody and p24 antigen may be used to detect acute HIV infection, but may not always be reactive in cases of early infection 3.
• Qualitative HIV-1 NATs can detect HIV-1 subtypes/circulating recombinant forms/group samples with high analytical sensitivity 4.
• Repeat testing and erythrocyte typing can help confirm or rule out laboratory error or specimen mishandling in cases of false-positive results 2.