Measurement uncertainty: practical problems encountered by accredited testing laboratories

Abstract

Following the introduction of ISO 17025 in 1999, all accredited testing laboratories have started to implement a procedure for estimating measurement uncertainties for the analytical methods that they employ. These procedures and uncertainties are an integral part of the quality system of the accredited laboratory and are therefore reviewed during audits by the accreditation bodies. In January/February 2004 the status of measurement uncertainties available at accredited testing laboratories was evaluated. It was found that most laboratory customers do not make use nor want to make use of the available measurement uncertainties. Furthermore, the current lack of standardisation has caused the estimated measurement uncertainties to vary widely, even for the simplest determinations.