This in vivo procedure is designed to test the ability of hygienic handwash agents to reduce levels of selected infectious viruses from experimentally contaminated fingerpads of adult volunteers. Since the two thumbpads and all eight fingerpads can be used in any given test, it allows for the incorporation of input virus control (two), amount of virus remaining after the inoculum has been allowed to dry (two), virus eliminated after treatment with a control or reference solution (two), and up to four replicates to assess the virus-eliminating efficiency of the product under test. No more than 100 μL of the virus suspension are required to complete one test. The results of testing with this test method may form the basis for confirmatory tests using a suitable whole-hand test protocol.

This test method is designed to be performed by a trained individual, who is responsible for choosing the appropriate host system for the test virus and applying the techniques necessary for propagation and maintenance of host and test virus. For a reference text, refer to Schmidt and Emmons (7).

Whereas, this test method relates to testing with viruses of human origin, it can be readily adapted to work with bacteria, fungi, protozoa and bacteriophages.

Infectious microorganisms left on hands after washing can be reduced further by drying the washed hands with paper, cloth, or warm air (8). A step for the drying of fingerpads after exposure to the control or test solution, therefore, has not been included to avoid virus removal by the drying process itself.

This test method is not meant for use with surgical hand scrubs or preoperative skin preps.

The amount of virus on each fingerpad after the drying of the inoculum should not be less than 10⁴ infectious units that would permit the detection of up to a 4 log₁₀ reduction in the infectivity titer of the virus by a given product under the conditions of this test method.