Validation fitness for purpose

For food safety and quality control, a number of other CRMs would be very much welcomed. Many requests are made for matrix matched CRMs and PTMs. Especially official food and feed control laboratories and moreover the Community and National Reference Laboratories are dependent on fit-for-purpose validated analytical methods and real matrix reference materials. 

Backen, A. C., J. Cummings, C. Mitchell, G. Jayson, T. H. Ward, and C. Dive. 2009. "Fit for purpose" validation of SearchLight multiplex ELISAs of angiogenesis for clinical trial use. /. Immunol. Methods 342 106-14. 

Parallelism, or linearity of dilution in biological samples, is a practical approach in a fit-for-purpose validation for new biomarkers. Preparing and analyzing dilutions of individual samples containing measurable amounts of endogenous... 

Brach-Papa, C., Van Bocxstaele, M., Ponzevera, E., and Quetel, C.R. (2009) Fit for purpose validated method for the determination of the strontium isotopic signature in mineral water samples by multi-collector inductively coupled plasma mass spectrometry. Spectrochim. Acta B, 64, 229-234. 

Expressing the design output in terms that can be verified and validated means that the requirements for the product or service need to be defined and documented. The design input requirements should have been expressed in a way that would allow a number of possible solutions. The design output requirements should therefore be expressed as all the inherent features and characteristics of the design that reflect a product which will satisfy these requirements. Hence it should fulfill the stated or implied needs, i.e. be fit for purpose. 

LGC - VAM Publications (i) The Fitness for Purpose of Analytical Methods, A Laboratory Guide to Method Validation and Related Topics, (2) Practical Statistics for the Analytical Scientist A Bench Guide By TJ Farrant, (3) Trace Analysis A structured Approach to Obtaining Reliable Results By E Pritchard, (4) Quantifying Uncertainty in Analytical Measurement, and (5) Quality in the Analytical Chemistry Laboratory. LGC/RSC Publications, London, England. 

J.D. MacNeU, J. Patterson, and V. Martz, Validation of analytical methods - proving your method is fit for purpose, in Principles and Practices of Method Vahdation, ed. A. Flajgelj and A. Ambrus, MPG Books, Bodmin, pp. 100-107 (2000). 

In this article, an analytical method is defined as series of procedures from receipt of a sample to final determination of the residue. Validation is the process of verifying that a method is fit for purpose. Typically, validation follows completion of the development of a method. Validated analytical data are essential for monitoring of pesticide residues and control of legal residue limits. Analysts must provide information to demonstrate that a method intended for these purposes is capable of providing adequate specificity, accuracy and precision, at relevant analyte concentrations and in all matrices analyzed. 

If no method exists for the analysis required, then either an existing method has to be adapted or a new method developed. The adapted or developed method will need to be optimized and the controls required identified, hence ensuring that the method can be used routinely in the laboratory. Evidence is then collected so as to demonstrate that the method is fit for purpose . The extent of validation, i.e. the amount of effort that needs to be applied, depends on the details of the problem and the information already available. Figure 4.3 indicates an approach that can be used to decide on the extent of validation required. The answer to DQ 4.2 has already mentioned that the customer may request a particular method. If... 

The validation is therefore not complete until there is a detailed description of the method and records of the validation study. A responsible person needs to sign that the method meets the requirements, i.e. it is fit for purpose . The documentation facilitates the consistent application of the method, within its scope and defined performance parameters. This, in turn, helps ensure that when the method is applied in different laboratories or at different times, the measurand is the same and that the measurement results are comparable. Documentation is also required for quality assurance, regulatory and contractual purposes. 

What is essential in establishing traceability is that the measurand is specified unambiguously. This may be, e.g. in terms of extractable cadmium from soil by using a named acid mix or the concentration of a metal in a particular oxidation state, e.g. Fe(n) or Fe(m). The units used to report the result should also be known and acceptable SI units are preferred. The method used will be validated and if used in accordance with the written procedures should produce results that are fit for purpose . The class of glassware to be used will be specified in the method procedure, e.g. Class A pipettes and volumetric flasks, as these are manufactured to a specified tolerance. Instruments will be regularly calibrated and their performance verified daily. In terms of the chemicals used, these will... 

All equipment has limitations, for example, the amount of a substance it can detect or the accuracy with which it can make a measurement. If you attempt to make the equipment perform beyond its capabilities, it does not matter how carefully the equipment is operated, it will not be possible to get meaningful results. In terms of a particular instrument, fitness for purpose is interpreted as having appropriate performance capability to do the work required. This applies to all equipment, large or small. For example, a stirrer needs to perform the intended task satisfactorily while remaining essentially inert. There is a formal process for assessing the suitability of equipment to perform a given task - this is called Equipment Qualification or Equipment Validation. This is dealt with in Section 5.6.3. 

By using the combination of specific method accreditation and generic accreditation it will be possible for laboratories to be accredited for all the analyses of which they are capable and competent to undertake. Method performance validation data demonstrating that the method was fit-for-purpose shall be demonstrated before the test result is released and method performance shall be monitored by on-going quality-control techniques where applicable. It will be necessary for laboratories to be able to demonstrate quality-control procedures to ensure compliance with the EN 45001 Standard,3 an example of which would be compliance with the ISO/AOAC/IUPAC Guidelines on Internal Quality Control in Analytical Chemistry Laboratories.12... 

Analytical methods should be validated as fit-for-purpose before use by a laboratory. Laboratories should ensure that, as a minimum, the methods they use are fully documented, laboratory staff trained in their use and control mechanisms established to ensure that the procedures are under statistical control. 

A process or facility fit assessment needs to be performed and involves translating the transferring site s process into a fit-for-purpose process within the manufacturing facility (Worsham, 2010). A comprehensive appraisal of the process requirements versus facility capabilities should be performed. This can help avoid unanticipated issues, which could lead to either unexpected delays and/or hidden costs at a later stage. Any changes to the process to accommodate the needs of the facility could result in additional process validation requirements. Therefore, changes should be constrained to the absolute minimum, but may be still required to facilitate a commercially viable process. 

Bouabidi, A., Rozet, E., Fillet, M., Ziemons, E., Chapuzet, E., Mertens, B., Klinkenberg, R., Ceccato, A., Talbi, M., Streel, B., Bouklouze, A., Boulanger, B., Hubert, P. Critical analysis of several analytical method validation strategies in the framework of the fit for purpose concept. J. Chromatogr. A., 1217, 2010, 3180-3192. 

A validation protocol adapted from the experiences during the method development defines the scope of the validation study (goal of the study, regulating guidelines, key method parameters, etc.). To investigate the adequate method performance, these features (e.g., range of analyte concentration), together with a statement of any fitness-for-purpose criteria, have to be specified in the validation protocol. A basic check has to provide that the reasonable assumptions about the principles of the method are not seriously flawed. In this process, sources of error in analysis have to be listed (Table 4) and their effects have to be checked. The validation should, as far as possible, be conducted to provide a realistic survey of the number... 

System suitability Use of appropriate assay controls to determine if a particular run is valid. May also include assay fit-for-purpose evaluations, such as stability indicating methods, etc. 

Method validation Basic method validation (short-term use, fit for purpose, little robustness), data will see expert eye prior to release Extended method validation, robustness and ruggedness tests important for unsupervised operation... 

Validation of analytical methods is important both from the standpoint of good science and to satisfy regulators of the reliability of results reported in dossiers. When approaching validation of any analytical method, one must always ensure that the method is fit for purpose. The amount of resource should be appropriate to the phase of development and the degree to which the process is defined and the methods finalised. 

Method Validation is the process of estabhshing the performance characteristics and limitations of a method and of verifying that a method is fit for purpose, i.e. for use for solving a particular analytical problem. 

Instrument validation should show that an instrament is able to perform according to its design specification. This can be done for example by means of calibration or performance checks [Eurachem Guide Fit for Purpose]... 

Fitness for purpose is the ultimate goal of the person doing the job in the laboratory, especially for the choice of method and instrumentation used to carry out an analysis. The validation of the analytical method is the important part to guarantee the fitness. 

Validation of analytical methods We all know that validation is to assess fitness for intended purpose. It was therefore logical to combine the separate chapters on Fit for purpose and Validation in the first edition into one chapter. 

FIGURE 2 Role of method validation in quality of analytical measurements. Validation is the process to demonstrate the fitness for purpose of the analytical system [4,8,14,15]. 

Traceability and MU both form parts of the purpose of an analytical method. Validation plays an important role here, in the sense that it confirms the fitness-for-purpose of a particular analytical method [4]. The ISO definition of validation is confirmation by examination and provision of objective evidence that the particular requirements of a specified intended use are fulfilled [7]. Validation is the tool used to demonstrate that a specific analytical method actually measures what it is intended to measure and thus is suitable for its intended purpose [2,11]. In Section 8.2.3, the classical method validation approach is described based on the evaluation of a number of method performance parameters. Summarized, the cri-teria-based validation process consists of precision and bias studies, a check for... 

The error of an analytical result is related to the (in)accuracy of an analytical method and consists of a systematic component and a random component [14]. Precision and bias studies form the basis for evaluation of the accuracy of an analytical method [18]. The accuracy of results only relates to the fitness for purpose of an analytical system assessed by method validation. Reliability of results however has to do with more than method validation alone. MU is more than just a singlefigure expression of accuracy. It covers all sources of errors which are relevant for all analyte concentration levels. MU is a key indicator of both fitness for purpose and reliability of results, binding together the ideas of fitness for purpose and quality control (QC) and thus covering the whole QA system [4,37]. 

Before any method validation is started, the scope of validation must be fixed, comprising both the analytical system and the analytical requirement. A description of the analytical system includes the purpose and type of method, the type and concentration range of analyte(s) being measured, the types of material or matrices for which the method is applied, and a method protocol. On the basis of a good analysis lies a clear specification of the analytical requirement. The latter reflects the minimum fitness-for-purpose criteria or the different performance criteria the method must meet in order to solve the particular problem. For example, a minimum precision (RSD, see below) of 5% may be required or a limit of detection (LOD) of 0.1% (w/w) [2,4,15,58]. The established criteria for performance characteristics form the basis of the final acceptability of analytical data and of the validated method [58]. 

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