Assessing the efficacy and cost of detergents used in a primary care automated washer disinfector.

BACKGROUND

Cleaning of re-usable medical devices is a critical control point in the decontamination cycle, although defined end-points of the process are controversial.

OBJECTIVE

Investigate cleaning efficacy and cost of different detergent classes in an automated washer disinfector (AWD) designed for dental practice.

METHODS

Loads comprised test soiled dental hand instruments in cassettes and extraction forceps. Residual protein assayed using the International standard method (ISO 15883-5:2005) 1% SDS elution with ortho-phthalaldehyde (OPA) or GBox technology (on instrument OPA analysis). Short (60 minutes) and long (97 minutes) AWD cycles were used with four different classes of detergents, tap water and reverse osmosis water.

RESULTS

SDS elution analysis (N = 612 instruments) demonstrated four detergents with both wash cycles achieved equivalent cleanliness levels and below a threshold of 200 μg protein/instrument. GBox methodology (N = 575) using UK Department of Health threshold of 5 μg/instrument side demonstrated that tap water performed with the greatest efficacy for all types of instruments and cycle types.

CONCLUSIONS

Using International standard methodology, different detergent classes had equivalence in cleaning efficacy. Cheaper detergents used in this study performed with similar efficacy to more expensive solutions. Findings emphasise the importance of validating the detergent (type and concentration) for each AWD.