Fluorescence-assay on traces of protein on re-usable medical devices: cleaning efficiency

The cleaning of re-usable medical devices before disinfection or sterilizat ion is recognized as being an essential phase. Detection of residual protei ns can be used to validate the process, provided a sufficiently sensitive m ethod is employed. A fluorescent method is presented, using orthophtalaldeh yde (OPA) bound to N,N dimethyl-2-mercaptoethylammonium, to demonstrate the presence of amino acids on a medical device following cleaning. The sensit ivity of this method (10(-5) g/l) was assessed and the applicability of thi s detection technique is verified, using three types of carriers (steel bla des, glass tubes or ceramic penicylinders), three types of contaminants (ye ast extract, bovine albumin with native sheep's blood and formaldehyde fixe d fibrin). In this context, studies involving formaldehyde-fixed fibrin are more sensitive and are to be recommended. (C) 1999 Elsevier Science B.V. A ll rights reserved.