Validity of test results

Asia Pacific Laboratory Accreditation Cooperation—APLAC) and Africa (Southern African Development Community in Accreditation—SADAC). Through these cooperations the importance of harmonization and conformity has been recognized. If countries adopt similar approaches to accreditation, and their accreditation organizations issue certificates with a harmonized information, it is much easier for clients to assess the validity of test results relating to cross-border trade, forensics, and health. 

If environmental conditions may have an influence on the validity of test results, the laboratory should have facilities to monitor and record these conditions, either continuously or at regular intervals. 

Replication involves repeating the experiment under identical conditions. It improves the reliability and validity of test results and is necessary to provide an estimate of experimental error. The number of replications completed is determined by time, cost, and sample constraints. However, the more replications completed, the better the estimate of experimental error and the more reliable the results. 

In all areas where raw materials, in-process drugs, or drugs are exposed, the following considerations apply to the extent necessary to prevent contamination. In laboratories these considerations only apply to the extent necessary to ensure the validity of test results. 

Application of the QSAR for screening purposes, testing the validity of test results, substitution of missing information, and (partial) replacement of experiments in chemicals testing. 

In terms of material approximation, phenomena such as cracking and compression nonlinearity or the presence of steel are smeared within the element integration area through equivalent stiffness and resistance modifications at the FE integration point Models of this type have been used in the parametric investigation of conventional or historical masonry construction and for the validation of test results. Complexity and computational cost and resources are the... 

The final step of method development is validation of the HPLC method. Optimisation of chromatographic selectivity [110], performance verification testing of HPLC equipment [591], validation of computerised LC systems [592] and validation of analysis results using HPLC-PDA [34] were reported. The feasibility of automated validation of HPLC methods has been demonstrated [593]. Interlaboratory transfer of HPLC methods has been described [594]. 

In the pharmaceutical industry, it is important that aU products are properly tested and vahdated prior to release for sale. One of the most important tests is the determination of tablet dissolution rate. In this procedure tablets are immersed in a suitable medium to mimic the action of the stomach and the release of the active ingredients monitored over a period of time. Automation of these procedures is obviously important for various reasons including cost, accuracy of analysis and for validation of the results according to good laboratory practice. 

The laboratory shall have qiralify control procedirres for monitoring the validity of tests and calibrations tmderlaken. Trends shoirld be detectable and, where practicable, statistical techniques shall be applied to the reviewing of the results (see chapter 12). 

Method validation seeks to quantify the likely accuracy of results by assessing both systematic and random effects on results. The properly related to systematic errors is the trueness, i.e. the closeness of agreement between the average value obtained from a large set of test results and an accepted reference value. The properly related to random errors is precision, i.e. the closeness of agreement between independent test results obtained under stipulated conditions. Accnracy is therefore, normally studied as tmeness and precision. 

In addition to review of test results, summary data, investigation reports, and other data, the print of the system should be reviewed when conducting the actual physical inspection. As pointed out, an accurate description and print of the system is needed in order to demonstrate that the system is validated. 

The standard recognizes the factors that determine the correctness and reliability of test results human factors, accommodation and environment, methods, equipment, sampling, and the handling of test items. In this list, measurement traceability is mentioned, but in fact metrological traceability, with measurement uncertainty and method validation, are really subsumed in methods. (subsection 5.4). The effect of each of these factors on measurement uncertainty will differ considerably among kinds of tests. 

Raw materials, both actives and excipients, can be a source of product variability. To limit this risk, there should be meaningful acceptance specifications and periodic confirmation of test results reported on the supplier s certificate of analysis. Also, purchases must be limited to previously qualified suppliers. A determination that such controls are in place should be part of any retrospective validation effort. 

The use of (3-casein as a test substrate presents, besides the importance of this protein in the food industry, advantages of releasing the hydrolysis from several structural limitations characteristic of many other potential native protein substrates. The use of this protein enabled a better understanding of the scope and validity of the results obtained with synthetic substrates. Additionally, the harnessing of mutated trypsins into the processing of (3-casein diversified the peptide products obtained. Most of the observed new cleavage sites were located in the hydrophobic portion of the protein. 

When analyzing the Q3 values it is clear that those are lower compared to the ones claimed by the authors in the original papers. This can basically be due to two factors poor statistics as a consequence of low number of test proteins, and lack of cross-validation of the results. 

That customer cannot pay for a wide range validation nor can the laboratory itself. The aim of the validation of test methods must always be to demonstrate that the method is fit for the intended purpose and that the results have an acceptable uncertainty. It is important that the rules of validation of test methods do not prevent the natural technological development from taking place. The laboratory does not expect (although it does want) outside financial help for validation of novel methods and in many cases tries to protect its new development from going to its competitors or from becoming generally available to all. 

Validation of testing methods always involves a balance between costs, risks and the technical capabilities of a given laboratory (NBN-EN-ISO-CEI 17025, 1999). Laboratory administrators must establish minimum quality requirements before starting the process of validation and implementation, or before starting the whole development process. Procedures of validation for a small laboratory could not be the same as for commercial validation of a new method, whether or not new kits from a manufacturer are used. There are many cases in which the range and uncertainty of the test result values can only be given in a simplified way due to lack of information. 

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