Test Methods for Disinfectants

Standardized tests for disinfectants have existed
worldwide for over 20 years.  However, not all tests
are the same. 

In order to normalize the test methods and the evaluations of the examination authorities, the European Committee for Normalization (CEN) created a technical committee for disinfectants, the CT216. These tests are preferred to all regional test methods. However, in this transitional period the “regional” tests that have existed for a long time (AFNOR, DGHM) are also acceptable. The AFNOR and DGHM standards may be found next to each other in the same dossier.

The test consists of three levels (see the rubric Forms and Explanations). Every test phase and level provides differentiated results, which allows the test to determine the strengths and weaknesses of a product.

• Phase 1 consists of a qualitative suspension test. This phase determines if the product possesses any effectiveness against target organisms. The disinfectant is diluted with water at various concentrations. These tests are qualitative, because the results show whether or not a product is effectiveness at the tested concentration. This phase is not mandatory for the dossier.
• Phase 2 / Level 1 consists of a quantitative suspension test (see rubric Forms and Explanations). The product is not only diluted with water, but also with a solution of impurities that simulates an organic contamination. Such a contamination often occurs in a dental practice, as the surfaces, instruments, or hands that require disinfection are often dirty. This phase is important, as certain substances react strongly with proteins, which causes the product to lose its effectiveness. This test is quantitative, because it calculates the number of eliminated target organisms, expressed as a log10 reduction factor.
• Phase 2 / Level 2 is a decisive test level, as the test conditions are comparable with the real-life circumstances of using a product in a practice (see rubric Forms and Explanations). In other words, this test phase simulates real-life conditions. As opposed to the previous tests, which are the same for all types of application, the tests of this last phase vary according to the proposed application area of the disinfectant. In Phase 2 / Level 2, the following tests are to be undertaken depending on the disinfectant's purpose. 

These three phases provide exact information regarding the effectiveness of a disinfectant against various pathogenic target organisms, the necessary concentrations, and the required contact times to reach a satisfactory effectiveness. As these tests are standardized, it is possible to have a reliable comparison of the compositions of the various active substances. For a product to be classified as effective, it must be able to considerably reduce the number of microorganisms, by more than:
      5 log10 for bacteria
      4 log10 for fungi
      4 log10 for viruses

The following proof of effectiveness should be attached to the disinfectant's form.