Analytical Standards and Certified Reference Materials

Standard ISO/IEC 17025 2005 requires a laboratory to have quality control procedures for monitoring the validity of tests and calibrations undertaken. This means that laboratories must perform internal performance-based quality control checks in accordance with Section 5.9 of ISO/IEC 17025 2005 as it applies to every test, technology, and/or parameter within their scope(s) of accreditation in order to demonstrate compliance with accreditation requirements. Reference or fortified material containing known amounts of analyte, at or near the permitted limit or the decision limit (a non-compliant control sample) as well as compliant control materials and reagent blanks should preferably be carried through the entire procedure simultaneously with each batch of test samples analyzed. Ideally, the control samples should also be very similar to test samples and stable over time. The laboratory should maintain a sufficient amount of control material to last for a significant time period (preferably a number of years) and at suitable analyte concentrations. 

CCP(j More sensitive signai (detection during the screening process) 

CCa Less sensitive signai used for the identification (during the confirmation process) 

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