Clinics and Departments

Laboratory Services

Lab Dept:

Serology

Test Name:

HIV 1/2 ANTIBODY CONFIRMATORY EVALUATION

General Information

Lab Order Codes:

HIVCO

Synonyms:

W. Blot Anti-HIV; HTLV III; AIDS; Aquired Immune Deficiency Syndrome; HIV1 Antibody

CPT Codes:

86689 – Antibody; HTLV or HIV antibody, confirmatory test
86689 X2 – HIV type 1 and 2 (if appropriate)
86702 – HIV antibody type 2 (if appropriate)

Test Includes:

This confirmatory test evaluation begins with HIV-1 Western Blot (WB) analysis. If WB is negative, then HIV Antibody Type 2 (Anti-HIV 2) is performed at an additional charge.

If WB is indeterminate or unreadable, then both HIV Type 1 Antibody Confirmation by Immunofluorescence and HIV Antibody Type 2 are performed at an additional charge.

If HIV Antibody Type 2 is reactive, then HIV-2 Antibody, IBL will be sent to Focus Diagnostics for confirmatory testing at an additional charge.

See HIV Serologic Screening Algorithm for more information.

Logistics

Test Indications:

This test is intended for use with persons of unknown risk as an additional, more specific test for antibodies to HIV-1 and/or HIV-2 in serum or plasma specimens that are repeatedly reactive on testing by a Food and Drug Administration (FDA)-approved HIV antibody screening EIA or rapid HIV antibody test.

Supplemental testing by WB is recommended on serum specimens that are reactive by these rapid HIV antibody tests, even if the initial follow-up EIA results are non-reactive.

Lab Testing Sections:

Serology - Sendouts

Referred to:

Mayo Medical Laboratories (MML Test: 23878)

Phone Numbers:

MIN Lab: 612-813-6280

STP Lab: 651-220-6550

Test Availability:

Daily, 24 hours

Turnaround Time:

1 – 3 days

Special Instructions:

N/A

Specimen

Specimen Type:

Blood

Container:

Red top tube

Draw Volume:

4.8 mL (Minimum: 1.2 mL) blood

Processed Volume:

1.6 mL (Minimum: 0.4 mL) serum

Collection:

Routine venipuncture

Special Processing:

N/A

Patient Preparation:

Lab Staff: Centrifuge specimen, remove serum aliquot and send specimen in a plastic, screw top tube. Send specimen frozen. Forward promptly.

Sample Rejection:

Mislabeled or unlabeled specimens, specimens other than serum

Interpretive

Reference Range:

Negative

If this test is ordered as a follow-up test on a patient with a reactive rapid HIV antibody test result, the CDC recommends supplemental testing with WB, even if EIA result is negative.

Critical Values:

N/A

Limitations:

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

Although persistently positive HIV-1 WB indicatesHIV-1 infection, a diagnosis of AIDS can only be made based on the case definition of AIDS established by the CDC.

High-risk individuals with reactive rapid HIV antibody test results but negative routine HIV-1/2 antibody screening tests and indeterminate or negative HIV-1 WB results, should be retested in 2 to 4 weeks. Repeat testing may be done by combination HIV-1 Antibody WB with either rapid HIV antibody or routine HIV-1/2 antibody screen test.

Positive HIV antibody WB results in infants of < or =18 months of age and born to HIV-infected mothers may indicate passive transfer of maternal HIV antibodies. Serologic tests (screening and confirmatory) 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 should be made by virologic tests such as detection of HIV RNA or HIV proviral DNA.

Performance characteristics have not been established for the following specimen types: Cadaveric specimens, Specimens containing particulate matter

Methodology:

HIV-1 WB: Western Blot
HIV Type 1 IFA: Indirect Immunofluorescence
HIV Type 2: Enzyme Immunoassay (EIA
HIV Type 2 Immunoblot: Immunoblot

References:

Mayo Medical Laboratories June 2011

Updates:

4/6/2004: Test moved from Memorial Blood Center of Minneapolis to Mayo Medical Laboratories. Note: Test now reflexes to supplemental/confirmatory testing (with additional charges) when indicated by reactive findings.
9/27/2010: Specimen requirement updates.



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