Key words: latex gloves, holes, breaks, standards, virus barrier, risk, standards, tech support
A recent evaluation of the importance of holes in latex condoms indicated that condom breakage during use was more serious, when considering risk from infection of low titer, low infectivity viruses such as HIV. The present study done in DPS and DLS focused on a similar risk analysis for latex medical gloves. The standard quality assurance test for holes is the 1000 mL water leak test, where the AQL is 2.5% for surgical gloves (i.e., up to 2.5% may fail the test). This test can reliably detect laser-drilled holes down to 40 micron diameter in the fingers and to 20 microns in the palm. A study of virus penetration through small tears created with acupuncture needles demonstrated that there was far more virus penetration through holes that failed the water leak test (water leakage was detected at the puncture site) than those that passed the water leak test. Averaged over four brands of latex surgical gloves the total amount of virus penetration from water-detectable holes represented about 92% of the total penetration through all holes. In the case where risk of infection is proportional to volume of virus exposure (e.g., HIV), the water leak test identifies the holes that dominate risk and thus seems to be an adequate test for latex gloves. That is, a more sensitive test (one that can detect smaller holes) would not substantially reduce risk.
On the other hand, tears and other barrier breaches occur during use, particularly in the thumb and first finger tips. For example, 10 to 31% of gloves may fail the water leak test following use in typical clinical settings. In this case, virus exposure through the new holes would dominate that from any pre-existing holes, primarily because the number of such holes is approximately an order of magnitude higher. It is not known whether pre-existing holes lead to some breaks.
Would changing the AQL help reduce risk? Yes, for instances where glove wear is low, so that the pre-existing holes are important. Lowering the AQL to 1.25% should reduce virus exposure by about 50%. For instances where glove wear dominates risk, some means of reducing glove breakage during use is needed.