Human Immunodeficiency Virus Diagnostic Testing: 30 Years of Evolution

Area of Science:

• Immunology
• Virology
• Public Health

Background:

• The early Human Immunodeficiency Virus (HIV) epidemic was marked by a critical lack of diagnostic tests.
• Initial HIV antibody tests, developed in 1985, primarily screened blood products and had a significant test-negative window.
• First-generation assays detected IgG antibodies, becoming positive 6-12 weeks post-infection, necessitating confirmatory tests due to false positives.

Purpose of the Study:

• To trace the evolution of HIV testing technologies.
• To highlight advancements in reducing the window period for HIV detection.
• To discuss improvements in accuracy and the development of new algorithms for HIV assays.

Main Methods:

• Review of the historical development of HIV diagnostic assays.
• Description of successive generations of HIV tests, including antigen and antibody detection.
• Analysis of algorithm changes to accommodate new assay capabilities.

Main Results:

• HIV testing has evolved from first-generation IgG antibody detection (6-12 weeks) to fifth-generation assays.
• Fourth- and fifth-generation assays incorporate p24 antigen detection, shortening the window period to 11-14 days.
• Fifth-generation assays offer separate antigen and antibody results, enabling earlier and more accurate HIV infection detection around 2 weeks post-exposure.

Conclusions:

• Advancements in HIV testing technology have dramatically reduced the time to diagnosis.
• Modern HIV assays offer improved accuracy with fewer false positives.
• The evolution of HIV tests is crucial for timely intervention and management of the HIV epidemic.