Abstract
The laboratory diagnosis of HIV infection has progressed greatly since the introduction of the commercially prepared, HIV antibody assay in 1985. However, the antibody assay remains the gold standard since the sensitivity and specificity of properly performed tests exceed 99%. Recent progress in diagnostic test development includes the availabilily of reliable HIV p-24 antigen capture assays with improved sensitivity due lo the elimination of immune complexes of antibody and p-24 antigen and enhanced specificity due lo the availabilily of confirmatory (neutralizing) reagents. HIV culture procedures have been optimized and standardized with isolation rates of the virus from HIV antibody positive persons approaching 95%. This technology is labour intensive and requires special containment facilities. The polymerase chain reaction. and other amplification methods. such as the branched chain reaction. are used to search for the presence of HIV genclic informalion. These technologies are exquisitely sensitive but offer little routine advantage to the standard HIV anlibody assay. There are specific circumstances. such as the diagnosis of perinatal infections and measuring the efficacy of potential agents for the treatment of HIV disease. where this technology is appropriate. The unique performance characteristics of these two amplification procedures necessitate thal they be performed only in laboralories wilh adequate physical facilities and ongoing qualily assurance programs. Assays for determining the antiviral sensitivity of HIV to specific drugs and for phenotyping viral isolates have been developed in research centres and are presently being introduced into clinical laboratories across Canada.