HIV Duo Test: Detecting Both HIV-1 and HIV-2 Antibodies and Antigens

The HIV Duo test is a highly accurate diagnostic tool designed to detect antibodies and antigens related to both HIV-1 and HIV-2. This comprehensive testing method makes it an essential tool in HIV diagnostics.

What Does an HIV Duo Test Detect?

Yes, the HIV Duo test detects antibodies to the HIV-1 and HIV-2 strains of the virus, and it also detects the p24 antigen. The simultaneous detection of antigens and antibodies is why it is referred to as a "Duo" test. An antigen is a foreign substance that triggers the body to produce antibodies.

Understanding HIV-1 and HIV-2 Strains

There are two major types of the human immunodeficiency virus: HIV-1 and HIV-2. HIV-1, discovered first, is the most widespread type worldwide. HIV-2, on the other hand, is more than 55% genetically different from HIV-1. This genetic difference means that tests developed specifically to detect HIV-1 may not reliably detect HIV-2.

Third-generation, fourth-generation, and rapid tests are sensitive to HIV-2 antibodies, making them reliable for detecting this strain. Both HIV-1 and HIV-2 are associated with the same modes of transmission and cause similar opportunistic infections, potentially leading to an AIDS defining diagnosis. However, immunodeficiency may develop more slowly and may be milder in people infected with HIV-2. HIV-2 is also less infectious early in the course of infection and has a shorter duration of increased infectiousness compared to HIV-1.

Geographical Prevalence and Transmission

HIV-2 is predominantly found in western Africa and is becoming more common in India, though the numbers there remain relatively small. Small numbers of cases have also been observed in Portugal, France, other European countries, including the UK, and the Americas, often in individuals of west African origin or their sexual partners.

In my 30 years of experience working with individuals diagnosed with HIV, I encountered one patient who tested positive for both HIV-1 and HIV-2. She had only two sexual partners and was not an injecting drug user. It was discovered that her husband was bisexual and had been having unprotected sex with multiple men he met on the internet. He later died of HIV, and she tested positive for HIV-2. A year later, she had an unprotected encounter with her boyfriend, who had a history of injecting heroin. Both tested positive for HIV-1.

Conclusion

The HIV Duo test is crucial in identifying both HIV-1 and HIV-2, ensuring comprehensive diagnosis and management of the virus. It remains a vital tool in the fight against HIV, providing healthcare providers with the necessary information to detect and treat the virus accurately.