|User Facility Reporting Bulletin||Spring 1997|
FDA SCIENTISTS STUDY QUALITY ASSURANCE TESTS FOR LATEX GLOVESBy Ron Carey, Ph.D., and Dave Lytle, Ph.D.
Two types of latex gloves are used in healthcare facilities: patient examination gloves and surgeon’s gloves. The Food and Drug Administration (FDA) tests sample lots of gloves from domestic manufacturers and gloves being imported into the U.S. FDA and the manufacturers use the current American Society for Testing and Materials (ASTM) standard test for quality assurance of gloves. To detect holes in gloves, the gloves are filled with water and then examined for two minutes. Any water appearing on the outside of the glove is considered a leak and the glove fails.
For FDA, the acceptable quality level (AQL) is not more than 2.5% failure of the surgeon’s gloves and not more than 4% failure of the patient examination gloves. Lots that fail a manufacturer’s or FDA’s test must be reconditioned and brought into compliance or destroyed. The sensitivity of this water test can be judged by testing surgeon’s gloves that have holes deliberately made with a laser. Using this method, we can detect 40 micron (a micron = 0.0016 inch) holes in the fingers and approximately 20 micron holes in the palms. Gloves are intended to prevent the transfer of fluid between medical personnel and patients. Viruses found in blood, sweat, and other fluids are much smaller than the holes detectable by the water leak test. For example, the human immunodeficiency virus (HIV) is about 0.1 micron in diameter. The function of the water leak test is not to detect holes as small as HIV, but to provide quality assurance (QA), i.e., to assure manufacturers that their gloves are made as flawless as possible.
To further test the gloves’ ability to be penetrated by viruses, we filled gloves with a virus/saline suspension. Then, each finger was dipped into saline to see if any virus leaked out. Some small holes (as small as 2 microns) were detected in addition to those found with the water test. We concluded that most of the risk of exposure comes from the larger pinholes and that the risk from the smaller holes was not significant enough to warrant changing the ASTM test to one that could detect these smaller holes.
Other scientists performed additional tests on gloves that had been used in a clinic or in surgery. These tests have shown that most of the unwanted exposure to fluids comes from tears and breaks occurring during use. Leakage through pinholes that are not detected by QA tests is relatively unimportant. However, it is possible that holes present before use may act as initiation sites for the tears and breaks.
An individual’s risk of infection is related to the frequency and amount of exposure to virus-containing fluids. Given the small but finite possibility of infection via pinholes and the larger problem of tears and breaks, it is reasonable to consider changes in the AQL at this time to reduce unwanted exposure. Glove users should keep in mind that double gloving and intact skin beneath the gloves will continue to reduce the risk.
FDA will continue to monitor QA procedures for gloves with the goal of minimizing the potential for exposure to infectious agents for both healthcare workers and their patients. We will continue to research the reasons for glove failures and to determine if these failures are critical in infection control. FDA is working with ASTM to raise QA standards when needed.
Dr. Carey is Chief of the Hydrodynamics and Acoustics Branch in the Division of Physical Sciences. Dr. Lytle is a biophysicist in the Division of Life Sciences. Both are in CDRH’s Office of Science and Technology.
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