Evaluation of Apparatus Used to Test Liquid through Protective Materials: Comparison of a Modified Dot-Blot Apparatus to the ASTM Penetration Cell

摘要

Personal protective equipment (PPE), such as gowns used in the latest Ebola outbreak inWestern Africa, are critical in preventing the spread of deadly diseases. Appropriate test systemsand test soils are needed to adequately evaluate PPE. ASTM F903, Standard Test Methodfor Resistance of Materials Used in Protective Clothing to Penetration by Liquid, has been usedfor decades to test fabrics’ resistance to liquid penetration. However, this test apparatus requiresat least 60 mL of test solutions, is labor intensive, and has problems with leakage aroundthe gaskets. We compared the F903 test apparatus to a modified dot-blot apparatus to evaluatethe visual penetration of a blood test soil. A series of commercially available gowns anddrapes were tested in each apparatus. Using blood test soil at 2 psi, there was no statisticallysignificant difference between the two methods except for in one gown. By comparing thisgown in the ASTM test apparatus with and without a screen, the particular screen selecteddid not account for the difference between the dot-blot and F903 apparatuses; however, itis conceivable that a particular screen/fabric combination could account for this difference.The modified dot-blot apparatus was evaluated using three different test solutions: blood,vomit, and a labeled protein (goat anti-rabbit immunoglobulin G–horseradish peroxidase[GaR IgG-HRP]) in a blood test soil solution. This testing revealed significant difference in penetrationfor some of the PPE garments. The modified dot-blot had several large advantagesover the ASTM apparatus—over six times less specimen volume and no edge or gasket leakage.In addition, nitrocellulose can be easily incorporated into the modified dot-blot apparatus, enabling the trapping of viruses and proteins that penetrate PPE—thus permitting the use of antibodies to quickly andsensitively detect penetration.