ABSTRACT
4.4. Accreditation is granted to a laboratory for a specified set of activities (i.e. tests or calibrations) following assessment of that laboratory. Such assessments will typically include an examination of the analytical procedures in use, the quality system, and the quality documentation. The analytical procedures will be examined to ensure they are technically appropriate for the intended purpose and that they have been validated. The performance of tests may be witnessed to ensure documented procedures are being followed, and indeed can be followed. The laboratory’s performance in external proficiency testing schemes may also be examined. Assessment may additionally include a ‘‘performance audit,’’ where the laboratory is required to analyse samples supplied by the accrediting body and achieve acceptable levels of accuracy. This performance audit is effectively a form of proficiency testing (see Sec. 21).
