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Interpretive Handbook

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Test 81758 :
HIV-1 Antibody Confirmation by Immunofluorescence, Serum

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

HIV type 1 (HIV-1) is the major etiologic agent of AIDS. The virus is transmitted through sexual contact, by exposure to blood (including sharing contaminated needles and syringes) or certain blood products, or from an infected mother to her fetus or child during the perinatal period. HIV-1 has been isolated from patients with AIDS or AIDS-related complex and from healthy persons at high risk for AIDS. Although there are 2 types of AIDS-causing viruses, namely HIV-1 and HIV-2, infections with HIV-2 outside of West Africa are uncommon.


This assay can be used to confirm the presence of HIV-1-specific antibodies when the initial screening assay is repeatedly reactive.


See HIV Testing Algorithm (Fourth Generation Screening Assay) Including Follow-up of Reactive HIV Rapid Serologic Test Results in Special Instructions.

Useful For Suggests clinical disorders or settings where the test may be helpful

Confirmatory detection of HIV-1 antibodies in human serum specimens that are repeatedly reactive by antibody screening assays or showed indeterminate or unreadable results by HIV-1 antibody Western blot

Interpretation Provides information to assist in interpretation of the test results

A negative result indicates the absence of HIV-1 specific antibodies.


A positive result indicates the presence of HIV-1 specific antibodies.


An indeterminate result does not imply that HIV-1 antibodies are present or absent in the serum specimen. Rather, it indicates that HIV-1 antibody status of the specimen cannot be resolved through the use of this assay. The correct approach in such situations should be based on subsequent repeat testing and the patient's clinical findings.


See HIV Testing Algorithm (Fourth Generation Screening Assay) Including Follow-up of Reactive HIV Rapid Serology Test Results in Special Instructions.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

This test is not offered for maternal/newborn HIV-1 antibody confirmation for specimens originating in New York.


Some individuals infected with HIV-2 may have antibodies that can bind to viral antigens present on the HIV-1 antibody immunofluorescence assay (IFA) slides.


Specimens from icteric patients may cause false-positive or indeterminate test results.


This assay is not FDA-approved for testing cadaveric or hemolyzed specimens.


Assay performance characteristics have not been established for the following types of serum specimens:

-Grossly icteric (total bilirubin level of >20 mg/dL)

-Grossly lipemic (triglyceride level of > or =500 mg/dL)

-Grossly hemolyzed (hemoglobin level of > or =1800 mg/dL)

-Presence of particulate matter

-Cadaveric specimens

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.


See HIV Serologic Interpretive Guide in Special Instructions for further interpretive information.

Clinical References Provides recommendations for further in-depth reading of a clinical nature

1. Sullivan MT, Mucke H, Kadey SD, et al: Evaluation of an indirect immunofluorescence assay for confirmation of human immunodeficiency virus type 1 antibody in U.S. blood donor sera. J Clin Microbiol 1992;30:2509-2510

2. Branson BM, Handsfield HH, Lampe MA, et al: Centers for Disease Control and Prevention: Revised recommendations for HIV testing of adults, adolescents, and pregnant women in health-care settings. MMWR Recomm Rep 2006;55;1-17

3. Hariri S, McKenna MT: Epidemiology of human immunodeficiency virus in the United States. Clini Microbiol Rev 2007;20:478-488