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Test ID: HIV2L HIV-2 Antibody Confirmation, Serum

Reporting Name

HIV-2 Ab Confirmation, S

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

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 measured 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 combined HIV-1 and HIV-2 antibodies or HIV-2 antibodies alone, currently there is only one FDA-approved supplemental (confirmatory) HIV-2 serologic assay for clinical use in the United States.

Interpretation

Negative results for HIV-2 antibodies usually indicate the absence of HIV-2 infection. However, in patients with reactive initial combined HIV-1/-2 antigen and antibody test results, such negative results do not rule-out acute or early HIV-2 infection. If acute or early HIV-2 infection is suspected, detection of HIV-2 DNA/RNA (FHV2Q / HIV-2 DNA/RNA Qualitative Real-Time PCR) is recommended, based on the patient's clinical and epidemiologic exposure history.

 

Positive HIV-2 antibody results indicate the presence of HIV-2 infection. Additional testing with a new whole blood specimen for HIV-2 DNA/RNA (FHV2Q / HIV-2 DNA/RNA Qualitative Real-Time PCR) is recommended to verify and confirm the diagnosis of HIV-2 infection prior to initiating antiretroviral treatment.

 

Indeterminate HIV-2 antibody results may be due to acute HIV-1 infection or very early HIV-2 infection (in individuals with risk factors). If acute HIV-1 infection or early HIV-2 infection is suspected, detection of HIV-1 RNA (HIVQN / HIV-1 RNA Detection and Quantification, Plasma) and/or HIV-2 DNA/RNA (FHV2Q / HIV-2 HIV-2 DNA/RNA Qualitative Real-Time PCR) is recommended, depending on the epidemiologic exposure history.

Analytic Time

1 day

Day(s) and Time(s) Performed

Monday through Friday; Varies

Clinical Reference

1. Campbell-Yesufu OT, Gandhi RT: Update on human immunodeficiency virus (HIV)-2 infection. 2011;52(6):780-787

2. Centers for Disease Control and Prevention and Association of Public Health Laboratories. Laboratory testing for the diagnosis of HIV infection: Updated recommendations. June 27, 2014. Available at http://stacks.cdc.gov/view/cdc/23447

3. Malloch L, Kadivar K, Putz J, et al: Comparative evaluation of the Bio-Rad Geenius HIV-1/2 confirmatory assay and the Bio-Rad Multispot HIV-1/2 rapid test as an alternative differentiation assay for CLSI M53 algorithm-I. J Clin Virol 2013;58(suppl. 1):e85-e91

4. Montesinos I, Eykmans J, Delforge ML: Evaluation of the Bio-Rad Geenius HIV-1/2 test as confirmatory assay. J Clin Virol 2014;60:399-401

5. Mor O, Milequir F, Michaeli M, et al: Evaluation of the Bio-Rad Geenius HIV 1/2 assay as an alternative to the INNO-LIA HIV 1/2 assay for confirmation of HIV infection. J Clin Microbiol 2014;52:2677-2679

6. Abbate I, Pergola C, Pisciotta M, et al:  Evaluation in a clinical setting of the performances of a new rapid confirmatory assay for HIV-1/2 serodiagnosis. J Clin Virol 2014;61:166-169

Method Name

Rapid Immunochromatographic Assay

Specimen Type

Serum


Advisory Information


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

 

Screening, supplemental, or confirmatory serologic tests for HIV-2 antibodies cannot distinguish between active HIV-2 infection and passive transfer of maternal HIV-2 antibodies in infants during the postnatal period (up to 2 years). Diagnosis of HIV-2 infection in newborns and infants of less than 2 years old should be made by consistently positive nucleic acid test results, such as the presence of HIV-2 DNA/RNA (FHV2Q / HIV-2 DNA/RNA Qualitative Real-Time PCR).

 

New York State clients: This test should not be requested for maternal/newborn HIV screening on specimens originating in New York State, due to state regulatory requirements for expedited result reporting.



Necessary Information


Date of collection is required.



Specimen Required


Collection Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Submission Container/Tube: Plastic vial

Specimen Volume: 0.5 mL

Collection Instructions:

1. Centrifuge blood collection tube per collection tube manufacturer's instructions (eg, centrifuge and aliquot within 2 hours of collection for BD Vacutainer tubes).

2. Aliquot serum into plastic vial.


Specimen Minimum Volume

0.2 mL

Specimen Stability Information

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

Reference Values

Negative

Test Classification

This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

86689

LOINC Code Information

Test ID Test Order Name Order LOINC Value
HIV2L HIV-2 Ab Confirmation, S 81641-3

 

Result ID Test Result Name Result LOINC Value
61785 HIV-2 Ab Confirmation, S 81641-3
Mayo Clinic Laboratories | Neurology Catalog Additional Information:

mml-CNS-Infections