Home
HelpTest ID HIVCO HIV-1 and HIV-2 Antigen and Antibody Evaluation, Serum
Useful For
Screening for HIV-1 and/or HIV-2 infection in asymptomatic patients
Diagnosis of HIV-1 and/or HIV-2 infection in symptomatic patients
Follow-up testing of individuals with reactive results from rapid HIV tests
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| HIVDI | HIV Ab Confirm / Differentiation, S | Yes | No |
| HIV2L | HIV-2 Ab Confirmation, S | Yes | No |
Testing Algorithm
This test begins with HIV-1/-2 antigen and antibody screen by the chemiluminescence immunoassay method. If HIV-1/-2 screen result is reactive, then HIV-1/-2 antibody differentiation test (by membrane immunoconcentration method) is performed at an additional charge. Depending on the HIV-1 and HIV-2 antibody results of this differentiation test, subsequent reflex tests such as HIV-1 antibody confirmation by Western blot and HIV-2 antibody confirmation by line immunoassay will be performed when appropriate and at an additional charge.
See HIV Testing Algorithm (Fourth Generation Screening Assay) Including Follow-up of Reactive HIV Rapid Serologic Test Results in Special Instructions.
Special Instructions
Method Name
Chemiluminescent Microparticle Immunoassay
Reporting Name
HIV-1/-2 Ag and Ab Screen, SSpecimen Type
SerumCollection Container/Tube:
Preferred: Serum gel
Acceptable: Red top
Submission Container/Tube: Plastic vial
Specimen Volume: 3 mL
Collection Instructions: Spin down and remove serum from clot within 24 hours.
Additional Information: If specimens are autopsy or cadaver blood sources, the proper FDA-licensed assay is HV1CD / HIV-1 and HIV-2 Antibodies for Cadaveric or Hemolyzed Specimens, Serum.
General Request Form (T239) (http://www.mayomedicallaboratories.com/it-mmfiles/general-request-form.pdf)
Neurology Test Request Form-General (T732) (http://www.mayomedicallaboratories.com/it-mmfiles/neurology-request-form.pdf)
Specimen Minimum Volume
0.2 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Serum | Refrigerated (preferred) | 21 days |
| Frozen | 30 days | |
| Ambient | 36 hours |
Clinical Information
AIDS is caused by 2 known types of HIV. HIV type 1 (HIV-1) is found in patients with AIDS, AIDS-related complex, and asymptomatic infected individuals at high risk for AIDS. The virus is transmitted by sexual contact, by exposure to infected blood or blood products, or from an infected mother to her fetus or infant. HIV type 2 (HIV-2) infection is endemic only in West Africa, and it has been identified in individuals who had sexual relations with individuals from that geographic region. HIV-2 is similar to HIV-1 in viral morphology, overall genomic structure, and its ability to cause AIDS.
Antibodies against HIV-1 and HIV-2 are usually not detectable until 6 to 12 weeks following exposure and are almost always detectable by 12 months. They may fall to undetectable levels (ie, seroreversion) in the terminal stage of AIDS when the patient's immune system is severely depressed.
Routine serologic screening of patients at risk for HIV-1 or HIV-2 infection usually begins with a HIV-1/-2 antigen and/or antibody screening test, which may be performed by various FDA-approved assay methods, including rapid HIV antibody tests, enzyme immunoassays, and chemiluminescent immunoassays. In testing algorithms that begin with these methods, supplemental or confirmatory testing should be requested only for specimens that are repeatedly reactive by these methods according to assay manufacturers' instructions for use.
Reference Values
Negative
Cautions
This test is not offered as a screening or confirmatory test for blood donor specimens.
Reactive result of this assay does not differentiate among reactivity with HIV-1 p24 antigen, HIV-1 antibody, and HIV-2 antibody.
A reactive screening test result is not diagnostic for HIV infection and should be considered preliminary.
The positive predictive value of a reactive screening test result is highly dependent on the prevalence of HIV infection in the population tested. The lower the prevalence of HIV infection, the lower the positive predictive value and higher the false-positive rate of the test. Diagnosis of HIV infection must be based on positive results of the supplemental or confirmatory serologic or molecular tests.
Recipients of experimental HIV-1 vaccines may have false-reactive HIV antibody test results without infection due to the presence of HIV-1 antibodies.
Negative serologic or molecular HIV screening test results should be evaluated with caution in patients with clinical symptoms and/or a history of high-risk behavior for HIV infection. Repeat testing in 1 to 2 months is recommended in these at-risk individuals.
Screening, supplemental or confirmatory serologic tests for HIV-1 or HIV-2 antibodies cannot distinguish between active neonatal HIV infection and passive transfer of maternal HIV antibodies in infants during the postnatal period (up to 18 months). Diagnosis of HIV infection in newborns and infants up to 18 months should be made by virologic tests, such as detection of HIV RNA (HIVDQ / HIV-1 RNA Detection and Quantification, Plasma).
Assay performance characteristics have not been established for the following specimen characteristics:
-Grossly hemolyzed (hemoglobin level of >500 mg/dL)
-Grossly lipemic (triolein level of >1250 mg/dL)
-Grossly icteric (total bilirubin level of >20 mg/dL)
-Heat-inactivated specimens
-Cadaveric specimens
-Presence of particulate matter
Day(s) Performed
Monday through Saturday; Varies
Report Available
1 dayPerforming Laboratory
Mayo Medical Laboratories in Rochester
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
87389
G0475 (if appropriate)