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Test ID HIV2L HIV-2 Antibody Confirmation, Serum

Useful For

Confirmation of the presence of HIV-2 antibodies in patients with repeatedly reactive combined HIV-1 and HIV-2 antibody or HIV-2 antibody-only screening test results

 

Diagnosis of HIV-2 infection

Testing Algorithm

The following algorithms are available in Special Instructions:

-HIV-2 Testing Algorithm: Screening (Nonsymptomatic) Diagnostic (Symptomatic)

-HIV Testing Algorithm (Fourth Generation Screening Assay) Including Follow-up of Reactive HIV Rapid Serologic Test Results

Method Name

Rapid Immunochromatographic Assay

Reporting Name

HIV-2 Ab Confirmation, S

Specimen Type

Serum

Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Specimen Minimum Volume

0.2 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Frozen (preferred) 30 days
  Refrigerated  14 days
  Ambient  48 hours

Clinical Information

Human immunodeficiency virus type 2 (HIV-2) is a lentivirus, a retrovirus in the same genus (Lentiviridae) as HIV-1. It was first isolated in 1986 in West Africa, where it is currently endemic. As of June 2010, CDC has reported a total of 166 cases that met the CDC case definition of HIV-2 infection in the United States. Most of these cases were found in the northeastern United States, and the majority had a West African origin or connection.

                                

Compared to HIV-1 infection, HIV-2 infection is associated with slower rate of progression, low viral load (which may not be reliably measurable with current methods), slower rates of decline in CD4 cell count, and lower rates of transmission (sexually or vertically). Up to 95% of HIV-2-infected individuals are long-term nonprogressors, and individuals with undetectable HIV-2 viral load have similar survival rates as that of the uninfected population. However, HIV-2 does cause immunosuppression as well as AIDS with the same signs, symptoms, and opportunistic infections seen in HIV-1. Due to the rarity of HIV-2, there are scant data from controlled trials to inform management decisions.

 

Although there are several FDA-approved screening assays to detect both combined HIV-1 and HIV-2 antibodies or HIV-2 antibodies alone, currently there is only 1 FDA-approved supplemental (confirmatory) HIV-2 serologic assay for clinical use in the United States. Interpretation of visible band patterns is complicated due to the significant cross-reactivity between HIV-1 and HIV-2 antibodies in this assay.

Reference Values

Negative

This confirmatory assay should be ordered only on specimens that are reactive by an HIV-2 antibody screening immunoassay.

Cautions

Negative HIV-2 antibody supplemental (confirmatory) test results does not exclude the possibility of acute or early (<60 days from time of exposure) HIV-2 infection. Individuals suspected of having acute or early HIV-2 infection should be tested for qualitative HIV-2 DNA/RNA (FHV2Q / HIV-2 DNA/RNA Qualitative Real-Time PCR) or quantitative HIV-2 RNA.

                 

The US Association of Public Health Laboratories recommends verification of all first-time positive supplemental test results for the definitive diagnosis of HIV infection. A second serum specimen should be obtained from the patient and submitted for repeat testing to verify all first-time positive test results.

 

Although a positive HIV-2 antibody supplemental test result indicates HIV-2 infection, a diagnosis of AIDS can only be made based on the case definition established by the CDC. In many US states, positive HIV-2 antibody supplemental test results are required to be reported to the state department of health.

 

Individuals at risk for HIV-2 infection with indeterminate or negative HIV-2 antibody supplemental test results should be retested in 2 to 4 weeks. Repeat testing may be performed with HIV-2 serologic testing (HIV2M / HIV-2 Antibody Screen, Serum), or qualitative HIV-2 DNA/RNA (FHV2Q).

 

Positive HIV-2 antibody supplemental test results in infants of <18 month old and born to HIV-2-infected mothers may indicate passive transfer of maternal HIV-2 antibodies. Serologic tests (screening or supplemental) cannot distinguish between active HIV-2 infection and passive transfer of maternal HIV-2 antibodies during the postnatal period (up to 18 months). Diagnosis of HIV-2 infection in newborns and infants of <18 months old should be made by consistently positive nucleic acid test results, such as the presence of HIV-2 DNA/RNA (FHV2Q).

 

This test should be ordered only on sera that are repeatedly reactive by FDA-licensed combined HIV-1 and HIV-2 screening serologic tests, HIV-2 antibody-only screening tests, or rapid HIV antibody tests.

Day(s) Performed

Monday through Friday; Varies

Report Available

1 Day

Performing Laboratory

Mayo Medical Laboratories in Rochester

Test Classification

This test uses a reagent or kit labeled by the manufacturer as Research Use Only. Its performance characteristics were determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

86689

NY State Approved

Yes