More than 1.2 million people in the United States were living with HIV infection as of 2011, 14% of whom did not know they were infected. Another ~50,000 individuals are newly infected each year. Identification and treatment of HIV infection can lead to substantial benefits in terms of decreased transmission, morbidity, and death.
We have discontinued what used to be the conventional antibodies test for HIV virus because of the advent of a new generation antibodies test which refines the diagnosis of HIV infection in its initial stages. Our Nationwide Laboratory Partner, Quest Diagnostics, has worked with the CDC on key clinical studies to create an alternative algorithm and a new HIV test is now available through us with a demonstrated high sensitivity (99.7%) and specificity (100%) and which screens and confirms HIV-1/HIV-2 infection, including acute infection.
Introducing: HIV1 & HIV2 – 4th Generation Antibodies Assay $89.00
For the HIV-1 RNA by PCR Blood Test or for a Combo HIV1 & HIV2 – 4th Generation Antibodies Assay & HIV-1 RNA by PCR Blood Test go here>>>
The US Preventive Services Task Force thus recommends voluntary, opt-out, screening for all pregnant women and for individuals 15 to 65 years of age in regions where the prevalence of infection is ≥0.1%. Individual risk assessments determine the need for screening beyond this age range.
The importance of detecting HIV during the acute phase (before seroconversion) is increasingly recognized; the acute phases marked by high viral load and appears to contribute disproportionately to transmission.
The conventional HIV testing begins with a “third-generation” HIV-1/HIV-2 antibody immunoassay, followed by supplemental testing (eg, Western blot) to confirm repeatedly reactive results. This approach is highly sensitive and specific but has several drawbacks: it cannot detect acute infection; it does not readily differentiate between HIV-1 and HIV-2; and negative or indeterminate results on Western blots during early seroconversion can delay diagnosis.
An alternative algorithm proposed by the CDC and adopted by the Clinical Laboratory Standards Institute (CLSI) is designed to avoid these drawbacks. The alternative algorithm begins with (preferably) a “fourth-generation” combination assay that detects HIV p24 antigen in addition to HIV antibodies. Because HIV p24 antigen is detectable before antibodies (seroconversion), fourth-generation assays can detect HIV during acute infection; the inclusion of HIV-1 and HIV-2 antibodies allows detection after seroconversion, when p24 antigen becomes undetectable.
Fourth-generation assays have >99.7% sensitivity and >99.3% specificity for HIV infection and can identify most (>80%) acute infections that would otherwise require nucleic acid testing for detection. In general, they can detect infection 0 to 20 days (median, 5-7 days) before third-generation immunoassays.
Repeatedly reactive results on fourth-generation screening tests require confirmation with a supplemental test, such as an HIV-1/HIV-2 antibody differentiation assay. Differentiation between HIV-1 and HIV-2 antibodies can have treatment implications, as HIV-2 does not respond to some antiretroviral agents.
Differentiation tests also tend to detect antibodies earlier than Western blots. But like Western blots, HIV-1/HIV-2 antibody differentiation tests do not detect acute infection. HIV RNA testing is thus needed to resolve infection status in patients with positive results on the fourth-generation assay but negative results on the antibody differentiation test.