HIV – I & II (WESTERN BLOT) Test

The HIV-I & II Western Blot test is a laboratory test that detects antibodies directed against specific proteins of Human Immunodeficiency Virus (HIV) types 1 and 2. It was historically used as a supplemental or confirmatory test after a reactive HIV screening test.

Western Blot works by separating HIV proteins and identifying whether antibodies in the patient’s blood react with specific viral proteins. This provides more specific information than an initial screening assay.

However, Western Blot is no longer routinely recommended as the standard confirmatory test in many modern HIV testing algorithms. Current approaches generally use a combination of HIV antigen/antibody screening, HIV-1/HIV-2 differentiation testing, and, when necessary, an HIV-1 nucleic acid test (NAT). The appropriate follow-up depends on the initial screening result and the laboratory’s testing algorithm.

HIV – I & II (WESTERN BLOT) Test is Recommended for Individuals:

• Individuals with a reactive HIV screening test, when specifically requested as part of an established testing protocol
• People undergoing supplemental evaluation for possible HIV-1 or HIV-2 infection
• Individuals with clinical findings that require further HIV evaluation
• Patients whose initial HIV test results require additional laboratory clarification
• Individuals undergoing HIV testing under a protocol where Western Blot is specifically indicated

FAQs

1. What does the HIV Western Blot test detect?
It detects antibodies that react with specific HIV proteins, helping provide more specific information following an initial HIV screening result.

2. Is HIV Western Blot still used to confirm HIV infection?
Western Blot was historically widely used for HIV confirmation. However, modern HIV testing algorithms generally use antigen/antibody tests, HIV-1/HIV-2 differentiation assays, and HIV nucleic acid testing when required rather than relying on Western Blot alone.

3. Does a negative Western Blot completely rule out HIV infection?
Not necessarily, particularly if testing occurs during the early window period or if the overall testing sequence is incomplete. If there has been a recent exposure or conflicting test result, a healthcare professional can recommend the appropriate follow-up test and timing.