Saliva test for HIV compared with blood test
A saliva test used to diagnose the Human immunodeficiency virus (HIV) is comparable in accuracy to the traditional blood test. The oral HIV test has become one of the most popular tests because of its acceptability, ease of use and it is noninvasive, pain-free, and convenient and produces results in 20 minutes.
A meta-analysis carried out by scientists at the McGill University (Montreal, QC, Canada) compared studies worldwide, showed that the saliva HIV test, had the same accuracy as the blood test for high-risk populations. They computed the positive predicted values (PPVs) separately for specimens of oral mucosal transudate and whole blood and explored the variability of the PPV within specimen groups in low-prevalence and high-prevalence settings.
The results of the analysis showed that the saliva HIV test, the OraQuick advance rapid HIV-1/2 (OraSure Technologies Inc.; PA, USA) had the same accuracy as the blood test for high-risk populations. The test sensitivity was slightly reduced for low risk populations. The slightly lower sensitivity of the test in oral mucosal transudate compared with blood specimens is probably because of a lower quantity of HIV antibodies in oral mucosal transudate than in whole blood. The titer of HIV antibodies is also low in acute HIV infection before seroconversion, hence the increased possibility that oral testing might miss more acute HIV infections than tests with blood specimens because of its lower sensitivity.