How to Select a Test How to Select a Test MethodMethodMarlene MooreAdvanced Systems, Inc.mmoore@advancedsys.comJune 15, 2010

ObjectiveObjectivePresent process of selecting test

methods◦Based on TNI standard requirements◦Based on client requests

TNI RequirementTNI RequirementISO/IEC 17025Volume 1 Module 2Section 5.4.2

◦Plus othersMore Details

◦Chemistry – V1M4 – Section 1.4◦Microbiology – V1M5 – Section 1.4◦Others

Test MethodsTest MethodsIncludes sampling

◦Does your laboratory do sampling?Meets

◦Client needs◦Appropriate for the tests

Published standards preferred◦International ◦Regional◦National

Test MethodsTest 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

Test Method SelectionTest Method SelectionMethod 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

Test Method SelectionTest 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…

Client NotifiedClient NotifiedWhen 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the client is considered to be inappropriate or out of date◦Note: Lab responsible for correct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

DeviationsDeviationsDeviation 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!)

Definition - ValidationDefinition - 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)

ValidationValidationThe 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

Chemistry Specific (V1M4)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

Chemistry Specific (V1M4)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

Chemistry Specific (V1M4)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.

Chemistry Specific (V1M4)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.

Chemistry Specific Chemistry Specific (Cont’d)(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.

Method Selection CriteriaMethod Selection CriteriaMandated 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 variationsData comparability

PJLA 17

Method Appropriateness Method Appropriateness Method Validation

◦ASTM◦EPA ATP procedures◦Others

industry specific or need for sensitivity

◦Client or laboratory defined

Slide 18

Quality Control RecordsQuality Control RecordsDemonstration of Performance

◦Initial Demonstration LOD, LOQ Precision and Bias Selectivity

◦On-going Demonstration

Slide 19

Limit of Detection (LOD)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?

Slide 20

Limit of Quantitation Limit of Quantitation (LOQ)(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?

Slide 21

Initial EvaluationInitial EvaluationPrecision and Bias

◦Standard methods◦Non-Standard methods

Selectivity

Slide 22

On-going EvaluationOn-going EvaluationChemical Testing (V1M4)

◦DOC (1.6.3)◦Batch Quality Control (1.7.3)

Method Blanks Laboratory Control Sample Matrix Specific Controls

Slide 23

SelectivitySelectivity“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.”

Microbiology (V1M5)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.”

Microbiology (V1M5)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.”

Microbiology (V1M5)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.”

Microbiology (V1M5)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

Documentation Review 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

Slide 29

Contract ReviewContract ReviewHow 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?

SummarySummaryCheck the regulation (s)Check the permit Check client specificationPublished standardsNotify the ClientDocument performanceAppropriate for the intended use

Thank youThank youQuestions ?