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How to Select a Test Method Marlene Moore Advanced Systems, Inc. mmoore@advancedsys.com June 15, 2010
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Objective Present process of selecting test methods ◦ Based on TNI standard requirements ◦ Based on client requests
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TNI Requirement ISO/IEC 17025 Volume 1 Module 2 Section 5.4.2 ◦ Plus others More Details ◦ Chemistry – V1M4 – Section 1.4 ◦ Microbiology – V1M5 – Section 1.4 ◦ Others
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Test Methods Includes sampling ◦ Does your laboratory do sampling? Meets ◦ Client needs ◦ Appropriate for the tests Published standards preferred ◦ International ◦ Regional ◦ National
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Test Methods “The laboratory shall ensure that it uses the latest valid edition of a standard unless it is not appropriate or possible to do so. “ ◦ What does the above mean? Supplemented with additional details to ensure consistency
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Test Method Selection Method not specified by client ◦ Select appropriate methods that have been published either in international, regional or national standards, or by reputable technical organizations, or in relevant scientific texts or journals, or as specified by the manufacturer of the equipment ◦ Laboratory-developed methods or methods adopted by the laboratory may also be used if they are appropriate for the intended use and if they are validated ◦ The client shall be informed as to the method chosen
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Test Method Selection “The laboratory shall confirm that it can properly operate standard methods before introducing the tests.” If the standard method changes, the confirmation shall be repeated. ◦ NOT Standard Methods for the Examination of Water and Wastewater…
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Client Notified When the method proposed by the client is considered to be inappropriate or out of date ◦ Note: Lab responsible for correct method even if client specifies wrong method. Section 5.4.1 ◦ deviations from methods or method modifications
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Deviations Deviation from test methods shall occur only if the deviation has been documented, technically justified, authorized, and accepted by the client. (5.4.1) Has the method performance been defined and proven ◦ Validation (it is not a bad word!)
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Definition - Validation “Validation is the confirmation by examination and the provision of objective evidence that the particular requirements for a specific intended use are fulfilled.” ◦ (TNI-V1M2 - 5.4.5.1)
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Validation The laboratory shall validate non-standard methods, laboratory-designed/developed methods, standard methods used outside their intended scope, and amplifications and modifications of standard methods to confirm that the methods are fit for the intended use. The validation shall be as extensive as is necessary to meet the needs of the given application or field of application. The laboratory shall record the results obtained, the procedure used for the validation, and a statement as to whether the method is fit for the intended use. TNI – V1M2 - 5.4.5.2
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Chemistry Specific (V1M4) The laboratory shall validate standard methods via the procedures specified in Sections 1.5.2 and 1.5.3. ◦ Limit of Detection ◦ Limit of Quantitation ◦ Evaluation of Precision and Bias More later…..
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Chemistry Specific (V1M4) “The laboratory shall validate non-standard methods, laboratory-designed/developed methods, standard methods used outside their published scope, and amplifications and modifications of standard methods to confirm that the methods are fit for the intended use.” Minimum specified in Sections 1.5.2 and 1.5.3 and 1.5.4. ◦ Limit of Detection ◦ Limit of Quantitation ◦ Evaluation of Precision and Bias ◦ Selectivity More later…..
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Chemistry Specific (V1M4) A standard method is a test method issued by an organization generally recognized as competent to do so. When a laboratory is required to analyze a parameter by a specified method due to a regulatory requirement, the parameter/method combination is recognized as a standard method. If there is not a regulatory requirement for the parameter/method combination, the parameter/ method combination need not be validated under 1.5.1b) as a non-standard method if it can be analyzed by another similar standard method of the same matrix and technology.
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Chemistry Specific (V1M4) The inclusion of the parameter in the method shall meet all required calibration requirements and the quality control requirements of the method to which the parameter is being added. If no QC exists in the method, the laboratory shall adhere to the requirements outlined in the similar method. For example, when adding acetone to Method 624, the calibration and QC requirements shall follow Method 624. A method that meets the above requirement shall be identified in such a way so that there is no confusion that the method has been modified.
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Chemistry Specific (Cont’d) When it is necessary to use methods not covered by standard methods, these shall be subject to agreement with the client and shall include a clear specification of the client's requirements and the purpose of the environmental test. The method developed shall have been validated appropriately before use.
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Method Selection Criteria Mandated versus performance ◦ Data use plays a large role in selection Measurement of true versus apparent concentration ◦ what is measured by the method? Comparability of data ◦ what basis? Resolution of data variations Data comparability PJLA17
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Method Appropriateness Method Validation ◦ ASTM ◦ EPA ATP procedures ◦ Others industry specific or need for sensitivity ◦ Client or laboratory defined Slid e 18
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Quality Control Records Demonstration of Performance ◦ Initial Demonstration LOD, LOQ Precision and Bias Selectivity ◦ On-going Demonstration Slid e 19
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Limit of Detection (LOD) ◦ Verify annually unless not reported to LOD ◦ All steps of process ◦ Each quality system matrix ◦ Each analyte ◦ Each instrument ◦ No more than 3x LOD for single analyte ◦ No more than 4x LOD for multiple analytes ◦ Not required if no spiking solution such as temperature pH, TSS, BOD, titrations, colorimetric? Slid e 20
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Limit of Quantitation (LOQ) ◦ Verify annually if not done for LOD ◦ All steps of process ◦ Each quality system matrix ◦ Each analyte ◦ Each technology ◦ Concentration: 1-2 times the LOQ ◦ Within defined acceptance criteria ◦ Not required if no spiking solution such as pH TSS, BOD, titrations, colorimetric? Slid e 21
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Initial Evaluation Precision and Bias ◦ Standard methods ◦ Non-Standard methods Selectivity Slid e 22
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On-going Evaluation Chemical Testing (V1M4) ◦ DOC (1.6.3) ◦ Batch Quality Control (1.7.3) Method Blanks Laboratory Control Sample Matrix Specific Controls Slid e 23
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Selectivity “The laboratory shall evaluate selectivity by following the checks established within the method, which may include mass spectral tuning, second column confirmation, ICP inter- element interference checks, chromatography retention time windows, sample blanks, spectrochemical absorption or fluorescence profiles, co-precipitation evaluations, and electrode response factors.”
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Microbiology (V1M5) 1.4 – “ A standard method is a test method issued by an organization generally recognized as competent to do so. When a laboratory is required to analyze a parameter by a specified method due to a regulatory requirement, the parameter/method combination is recognized as a standard method. If there is not a regulatory requirement for the parameter/method combination, the parameter/method combination is recognized as a standard method if it can be analyzed by another similar standard method of the same matrix and technology.”
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Microbiology (V1M5) 1.4 – “When it is necessary to use methods not covered by standard methods, these shall be subject to agreement with the client and shall include a clear specification of the client's requirements and the purpose of the environmental test. The method developed shall have been validated appropriately before use.”
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Microbiology (V1M5) Validation – Non-standard methods, etc. ◦ “Accuracy – Use at least one (1) known pure reference culture at the anticipated environmental conditions, and compare the test method results to that of a reference or standard method. ◦ Precision – Perform at least ten (10) replicate analyses with both the proposed and reference method, using the target microorganisms of choice. The results shall show that the methods are not statistically different. ◦ Selectivity (sensitivity) – Verify all responses in at least ten (10) samples using mixed cultures that include the target organism(s), and at varying concentrations (microbial identification testing or equivalent processes may be used). Calculate the number of false positive and false negative results.”
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Microbiology (V1M5) Demonstration of Capability (1.6) ◦ Initial DOC If no DOC in method then 1.6.2.2 followed. ◦ On-going DOC Defined by laboratory from list of options in 1.6.3.2 Batch QC 1.7.3
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Documentation Review Are SOPs in-place for all work? Are they being followed? Is what the analyst(s) performed and the results of their work documented? Must allow historical reconstruction of the data Slid e 29
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Contract Review How are changes to scope of work or method deviations handled? How are clarifications to methods requested documented? How is the method selection reviewed? Who handles and documents discussions between client and laboratory?
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Summary Check the regulation (s) Check the permit Check client specification Published standards Notify the Client Document performance Appropriate for the intended use
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Thank you Questions ?
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