20-min oral test to detect HIV

100% Accurate Gum Swab Examination May Soon Replace Blood Test

New Delhi: A simple 20-minute gum swab test could soon tell you whether you are HIV positive or not.
In a breakthrough that could do away with the conventional HIV antibody test, through blood taken from the finger or the arm, scientists from McGill University Health Centre (MUHC), Canada, and Mahatma Gandhi Institute of Medical Sciences (MGIMS) in Sevagram have successfully tested an oral fluid-based HIV test that has proved 100% accurate.

Lead scientist Dr Nitika Pai from MUHC tested 450 individuals for HIV infection at MGIMS and found 32% of them to be HIV positive.
The team then compared the diagnostic accuracy of the OraQuick test from two samples — one obtained from oral fluid (gums) and the other from a blood-based finger stick — with traditional blood tests. Only one false positive case was recorded with the oral gum swab test, proving 99.7% specificity. While 66% of the subjects reported discomfort with the finger testing method, no similar discomfort was recorded during sample collection for the oral test.

Dr Rajnish Joshi from MGIMS, who conducted the tests with Dr Pai, told TOI that extracting blood from random subjects in field settings poses a severe logistical problem because it needs injecting syringes to draw blood and trained personnel to carry out the procedure for risk of needle stick injury.

''Now, all that one has to do is rub the stick against the gum twice, once against the upper jaw and then on the lower jaw, from one end to another, to collect oral mucosal transudate fluid, normally secreted in the oral cavity. The applicator on the stick, a strip of synthetic proteins, then detects HIV antibodies in blood in 20 minutes or less. Standard HIV tests with the help of blood make patients wait up to two weeks for results. According to the CDC Atlanta, 33% of testees never pick up their results. It also costs about Rs 200 and can be administered practically in any setting — a clinic, a bar or even a street corner,'' Dr Joshi said.

OraQuick test has been approved by the US Food and Drug Administration. But some studies had indicated that it was not sufficiently precise. As a result, CDC Atlanta had called for more definitive studies leading to this study in rural India.

''Based on our findings, the oral test is the preferred choice for HIV field testing by rural Indians,'' said Dr Pai, a physician epidemiologist supported by the Canadian HIV Trials Network. ''The advantages are that results are available within minutes and can also be performed by health workers with minimal training, eliminating the need for specialist laboratory technicians,'' she added.

''Rapid point-of-care HIV testing, which are non-invasive, simple, accurate and oral fluid-based, have the potential to make a big impact on HIV screening. They open the door to the possibility of home-based HIV testing,'' she said