Sorted By Test Name - Mayo Medical Laboratories

WBANF
32466
monitoring, the United States Department of Health and Human Services Panel on Antiretroviral
Guidelines for Adults and Adolescents defines virologic failure as a confirmed viral load of >200
copies/mL, which eliminates most cases of viremia resulting from isolated blips or assay variability.
Confirmed viral load rebound (ie, >200 copies/mL) on 2 separate tests obtained at least 2 to 4 weeks apart
should prompt a careful evaluation of patient's tolerance of current drug therapy, drug-drug interactions,
and patient adherence.
Reference Values:
Undetected
Clinical References: 1. Relucio K, Holodniy M: HIV-1 RNA and viral load. Clin Lab Med
2002;22:593-610 2. Thompson MA, Aberg JA, Cahn P, et al. Antiretroviral treatment of adult HIV
infection: 2010 recommendations of the International AIDS Society-USA panel. JAMA
2010;304:321-333 3. Panel on Antiretroviral Guidelines for Adults and Adolescents. Guidelines for the
use of antiretroviral agents in HIV-1-infected adults and adolescents. Department of Health and Human
Services. January 10, 2011;1–166. Available at:
http://www.aidsinfo.nih.gov/ContentFiles/AdultandAdolescentGL.pdf
HIV-1/-2 Antibody Confirmation Without Immunofluorescence
Assay, Serum
Clinical Information: AIDS is caused by at least 2 known types of HIV. HIV type 1 (HIV-1) was
isolated from patients with AIDS, AIDS-related complex, and asymptomatic infected individuals at high
risk for AIDS. The virus is transmitted by sexual contact, exposure to infected blood or blood products, or
from an infected mother to her fetus or infant. HIV type 2 (HIV-2) was isolated from patients in West
Africa in 1986. It appears to be endemic only in West Africa and it also 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 into undetectable levels in the terminal stage of AIDS. Routine serologic
screening of patients at risk for HIV-1 or HIV-2 infection usually begins with a HIV-1/-2 antibody
screening test, which may be performed by various FDA-approved assays, including rapid HIV antibody
tests, EIA, and chemiluminescent immunoassay (CIA) methods. In testing algorithms that begin with EIA
or CIA methods, confirmatory HIV antibody tests should only be ordered for patients who are found to be
reactive by routine HIV-1/-2 antibody screening tests or by rapid HIV antibody tests. However, for testing
algorithms that begin with rapid HIV antibody tests, confirmatory antibody testing should be performed
regardless of the result of the EIA or CIA tests. Individuals at risk for HIV infection may have negative
HIV antibody screening test results by EIA or CIA with indeterminate Western blot results (especially
during early stage of infection). Such individuals may be erroneously interpreted to not have HIV
infection, despite having reactive rapid HIV antibody test results.
Useful For: Confirmatory detection of HIV-1 and/or HIV-2 antibodies in patients with reactive
antibody screen or rapid HIV antibody results
Interpretation: An HIV-1 antibody Western blot (WB) result is interpreted as positive when at least 2
of the 3 following bands are present: p24, gp41, and gp120/160. A positive HIV-1 antibody WB result
following a reactive HIV-1/-2 antibody screening test, or rapid HIV antibody test, indicates infection with
HIV-1, but it does not indicate the stage of disease. In many states, positive confirmatory HIV antibody
test results are required to be reported to the state department of health. A negative HIV-1 antibody WB
result with either a reactive HIV-1/-2 antibody screening test or a reactive rapid HIV antibody test, in the
absence of signs, symptoms, or risk factors for HIV infection, probably indicates a false-positive
screening test or rapid test. However, a negative HIV-1 WB does not exclude the possibility of early
HIV-1 or HIV-2 infection. If the HIV-1 antibody WB test result is negative, the HIV-2 antibody test by
EIA will be performed automatically (at an additional charge). Indeterminate WB patterns can be found in
up to 15% of persons without evidence of HIV infection. If the HIV-1 antibody WB test result is
indeterminate, the HIV-2 antibody test by EIA will be performed automatically (at an additional charge).
Individuals at risk for HIV infections should undergo nucleic acid testing if acute HIV infection is
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