External quality assurance assessment scheme

The Committee was informed that the external quality assurance assessment scheme had been ongoing over the last five to six years. An 

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External Quality Assurance (EQA) schemes attempt to provide an independent assessment of a laboratory s performance usually with respect to a defined assay. Such schemes complement (and use) ICQ. The basis of the schemes is... 

A Proficiency Test (PT) is defined as the study of laboratory performance by means of ongoing interlaboratory test comparisons . It is also known as an external quality assessment scheme, external laboratory performance check or external quality assurance (EQA). There are many such schemes run by independent external bodies for different analytes in a variety of matrices. Evidence in published papers shows that the performance of analytical laboratories improves as a result of participating in Proficiency Testing schemes and the betw een-laboratory precision can improve, sometimes dramatically. This is especially true in the early years of participation. 

At a plasma/serum concentration of 0.98 mg/L, the within batch precision was found to be 2.1% (n = 48). Internal quality assurance is assessed by use of samples taken from a pooled collection of bovine serum, and the between batch precision is calculated monthly. Typical findings at a mean concentration of 1.14 mg Zn/L are an RSD of 1.8%. External Quality Assurance is by participation in a UK inter-laboratory scheme (Robens Institute. University of Surrey). 

Some of the most relevant procedures for the analysis of K-vitamers are brought together in Table 5. It should be clear that again LC is the technique of choice, as this technique is applied both to the sample cleanup and to the analytical measurement of vitamin Ki(20) in different matrices. As with all modern analytical programs, a keystone for success is a sound quality control and assessment strategy, which should always include the exchange of samples between different analytical laboratories and the use of round robin external quality assurance schemes wherever possible. 

To assure the accuracy and comparabihty of the results with other laboratories, an appropriate external quality assessment is necessary. For external quality control, participation in a round robin test is recommended. There are various quality control programs containing cadmium in blood and urine, e.g., the international program of the German External QuaUty Assessment Scheme (E-QUAS), where cadmium analysis can be tested for the concentration range found in occupational and environmental medicine [48], or the external quahty assessment schemes of the Centre of Toxicology in the National Institute of Public Health of Quebec [49]. 

Recognising the special difficulties for homoeopathic products to satisfy the standard requirements for proof of efficacy, the European Directive 92/73 was agreed and implemented in the UK with the Homoeopathic Registration Scheme. Under the scheme, efficacy is not a criterion of assessment, on the grounds that no therapeutic indications are claimed for the product and this must be conveyed on the label. Safety is assured by limiting the scheme to oral or external products and a sufficient dilution of the product technical data must be submitted to demonstrate adequate quality. 

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