THE ASSESSMENT OF THE BACTERICIDAL ACTIVITY OF SURFACE DISINFECTANTS .5. CORRELATION OF THE TESTS WITH PRACTICE

The objective of this study is to determine to what extent the value of a preparation for surface disinfection in practice can be predicted by the usual tests, namely the in vitro test in which the disinfectant is diluted in distilled water, in water of standardized hardness or in a 0.2% albumin solution, the European suspension test under clean and under dirty conditions, the Kelsey-Sykes test under clean conditions, the AOAC use-dilution method, the practical tests of the AFNOR, of the DGHM, the quantitative carrier test QCT and the quantitative surface disinfection test QSDT. Therefore the results of all these tests are compared to the ranking order of the efficacy of the same preparations in practice tests, in which slides contaminated with stool or infected urine are disinfected (Table 1). There is no correlation between the results of the suspension tests and those of the practice tests, but the practical tests (DGHM test, QCT and QSDT) correlate well with practice (Table 2). Practical tests (second stage of the testing schedule) are therefore necessary for the evaluation of surface disinfectants, as suspension tests alone will not suffice.