| Quality |
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| Quality assurance |
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Quality assurance and control forms an integrated part of the analyses performed and of the work of ALS Scandinavia as a whole.
Quality assurance (QA) is the generic term for all activities required to maintain quality in the analytical results. The QA activities affect many fields such as organization, training, equipment, methods, etc.
The QA is organized and documented within the laboratory´s QA system. The QA system is a prerequisite for laboratory accreditation. The accreditation is a third-party acknowledgement of competence and is comparable to ISO 9000 certification in industry. For a laboratory to be accredited, compliance with international QA standards must be confirmed both by an initial assessment and by recurrent audits. In Sweden, accreditation and control of accredited laboratories is the responsibility of SWEDAC. SWEDAC cooperates internationally with other accreditation bodies, which implies that its accreditation is accepted in several other countries. |
Accreditation by SWEDAC pertains to specific analytical methods. Non-accredited analyses are also subject to QA and many parts of the QA system are common to all analyses. However, accredited analyses must meet special requirements e g regarding documentation.
 Accreditation certificate from SWEDAC (Täby) [pdf]
Accreditation certificate from SWEDAC (Luleå) [pdf]
Accredited methods in Täby [pdf]
Accredited methods in Luleå [pdf]
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| Quality control |
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Quality Control (QC) is the specific control of an analysis to verify the results before reporting. There is also more general control of the laboratory's analytical methods and their use. QC is an important component of the QA system.
The most important tools for controlling chemical analyses are interlaboratory comparisons and certified reference materials.
In Interlaboratory Comparisons, several laboratories analyze subsamples of one and the same homogeneous sample. If a sufficient number of laboratories participate and the analytical methods are reliable, the resulting mean or median may serve as a reference value. ALS Scandinavia participates regularly in interlaboratory comparisons for trace metals in water, blood, urine etc. Please contact our Quality Manager for more information about interlaboratory comparisons. |
Certified Reference Materials (CRM) are authentic materials (e g seawater, plant material, steel etc) in which concentrations of various substances have been accurately determined by means of several analytical techniques and laboratories, usually in international cooperation. Many CRM:s are commercially available. The material is followed by a certificate with known (certified) values to which a laboratory can compare its results and thus check the accuracy in its own analysis. ALS Scandinavia routinely uses CRM:s in the analyses.
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| Control charts |
Validation of analytical methods |
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For all accredited analyses there are control charts showing long-term results for a reference sample. This sample is often a CRM. In each analysis, the reference sample is analyzed together with the ordinary unknown samples. The results statistics is used to calculate "action limits" representing certain concentration levels above and below the mean. If at any time the result for the reference sample falls outside these limits, the analysis is not approved. This prevents accidental errors from causing errors in reported results. The control charts are also evaluated yearly with respect to agreement with reference/certified values, precision (i e the agreement between analyses on different days), limits of detection and quantitation, and trends (changes over time). This evaluation reveals weaknesses and forms a basis for measures to continuously improve the analyses.
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Validating an analytical method means to experimentally test and to document that the method fulfils the requirements for its intended use. Within the drug industry, where analyses are usually strongly specialized for defined sample types, ALS Scandinavia often performs validation on a contract basis together with method development. Validation is normally carried out according to procedures that are internationally accepted (ICH Q2A, B), and which include the following analytical performance criteria:
Accuracy
Precision
Specificity
Detection limit
Quantification limit
Linearity
Range
Robustness
A validation project does not always include all the above items. It is based on a validation protocol, which is defined by the laboratory or by the customer, and on which both parties agree. The validation protocol may specify the requirements for the method, e g regarding detection limits. The final results are documented in a validation report. |
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