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Combined Interpretations of the 2003, 2009, and 2016 Standards that apply to Volume 1 of the 2016 TNI Standard


MODULE 4: CHEMISTRY TECHNICAL REQUIREMENTS
Section: 1.6

Question:  Currently our laboratory uses Work Groups for IDOC and DOC of the sample preparation methods (i.e., EPA 3005, EPA 3510, ... etc.) and the we perform IDOC and CDOC on individual analysts for the test methods (i.e., EPA 6020, EPA 8270, ... etc.).  This represents well our actual practice of having a formalized group of employees performing sample prep as a team effort, and then subsequent actual instrument analysis is performed by an individual. Because the 2009 Standard has been revised to no longer explicitly describe work groups, will it be required to DOC our prep group personnel individually under the 2009 Standard, or are these types of work groups still allowed to be DOCed as a formal team? As an alternative, under the 2009 Standard is it permissible to maintain DOC on the analyst as the individual responsible for the sample(s) for that test, with the prep team working under that DOCed analyst’s oversight?  This essentially wraps the sample prep and analysis together under a designated analyst who utilizes “assistant” individuals within the process. 

TNI Response:  Each individual analyst must have documentation on file that indicates that he/she is competent to perform the portion of the analysis for which he/she is responsible. Work cells may be used. The laboratory needs to define how the concept is used to demonstrate individual competence.

 

Question:  A laboratory in our program has requested clarification that the term "outside source" has the same or a different meaning from the term "secondary source."  The laboratory understands that a "secondary source" should be used for instrument calibration per NELAC 5.5.5.2.2.1.d but this is not required for demonstration of capability or determination of LOD or determination of LOQ.  The question is "Is 'outside source' the same as 'secondary source'?"  
TNI Response:  The term outside source is not equivalent to the term secondary source. The outside source cited in C.1 a) meant a source other than calibration standards. This is consistent with the definition of Quality Control Sample, which may be a Certified Reference Material, quality system matrix fortified by spiking, or actual samples fortified by spiking.  This language was deleted in the 2009 (and 2016) standards.  The SIR is obsolete.

 

Question:  I would like to have interpreted Appendix C – Demonstration of Capability C.1 paragraph 6.  and step a).  The test methods we are applying for NELAC accreditation are the EPA 500 methods for SDWA compliance testing.  These methods are mandatory test methods by both State and Federal regulation.  In paragraph 6 it states “following steps shall be performed if required by mandatory test method or regulation”. So my question is:  If a test method specifically has the IDCs to be completed by use of an LFB (not a QCS obtained from an outside source) then shouldn’t NELAC recognize these IDCs as acceptable for accreditation? I also interpret the language at a) that the QCS to be used for the DOC only needs be what we usually refer to as second source if the stock standards were prepared within the laboratory and not acquired through an outside source.

TNI Response:  The outside source cited in C.1 a) meant a source other than calibration standards. This is consistent with the definition of Quality Control Sample, which may be a Certified Reference Material, quality system matrix fortified by spiking, or actual samples fortified by spiking. If the laboratory's LFB meets the definition of a Quality Control Sample, the lab would be in compliance.  This language was deleted in the 2009 (and 2016) standards.  The SIR is obsolete.

 

Question:  We seem to have a difference of opinion in our lab. We have a manager that feels that the Table 2 of the EPA Method 548.1 give the criteria to be used for % Recovery for DOCs. They are stating that the Concentration used 100 shows a  95% recovery.  They are trying to change their acceptance to 95% +/- 20% Section 9.3 of the method states to use the R value from this table 2.   Aren't these only suggestions of R values? At the moment it is +/- 20% of the mean recovery

TNI Response:  Note: Laboratories should attempt to reconcile all differences in the interpretation of the standards and/or analytical methods with the applicable EPA Program, Regional Office and/or accreditation body. In reviewing Method 548.1, Revision 1.0, section 9.3 it is our interpretation, which concurred with one of EPA's Cincinnati's Chemist, that the laboratory's mean recovery +/-20% with an RSD of 30% is acceptable for the IDOC, then the laboratory may use the same values or tighter for DOCs in accordance with Chapter V, Appendix C. Table 2 of the method was developed only using 7 replicates, therefore it would be best for a laboratory to adhere to limits for accuracy and precision developed using their own mean recovery.  Nothing was changed in the 2009 or 2016 standards to suggest this SIR is still not relevant.

 

Question: Assessors require that each analyst perform an Initial Demonstration of Capability prior to running samples.  This IDOC is, as referenced in Appendix C, is 4 aliquots of a quality control sample.  5.5.4.2.2 states 'The laboratory shall confirm that it can properly operate all methods before introducing the environmental tests.  If the method changes, the confirmation shall be repeated.'  Since the definition of method does not include 'analyst', does the introduction of a new analyst mean the method has changed? 5.5.4.2.2 a) states (in part – I believe I have not left out any language germane to the question) ‘Prior to acceptance and institution of any method, satisfactory demonstration of method capability is required.  (See Appendix C and 5.5.2.6.b)’. 5.5.4.2.2. b) states ‘Thereafter, continuing demonstration of method performance, as per the quality control requirements in Appendix D (such as laboratory control samples) is required.’ 5.5.4.2.2 e) states ‘A demonstration of capability must be completed each time there is a change in instrument type, personnel, or method.’  Does the order in which these items are presented determine the requirements, such that a demonstration of capability is required prior to acceptance of any method, but thereafter laboratory control samples can be used to demonstrate an analyst’s (even a new analyst’s) capability?

TNI Response:  5.4.2.2.a and b refer to the institution of any method in the lab. Unless there is an analysis that does not require an analyst, the analyst is considered the lab for the purposes of DOC. 5.5.4.2.2.e requires a repeat of demonstration for each analyst or instrument type or method change. So if a new analyst is introduced, yes he/she must perform a DOC. No, the order in which items are presented does not determine the requirements.  This language was revised in the 2009 (and 2016) standards to focus on individuals.  The SIR is obsolete.

 

Question:  Is it necessary to perform continued proficiency for all 8 aroclors and toxaphene? Would it be acceptable to performed continued proficiency for only one pattern to meet this requirement?   

TNI Response:  For initial demonstrations of capability all analytes of interest would need to be analyzed: In this case all aroclors and Toxaphene. For the continuing demonstration of capability only the method required spiking analytes would be necessary.  Nothing was changed in the 2009 or 2016 standards to suggest this SIR is still not relevant. The requirement to analyze all analytes may be understood from the Standard language, however.

 

Question:  Section 5.5.4.2.2 states "Prior to acceptance and institution of any method, satisfactory demonstration of method capability is required. (See Appendix C and 5.5.2.6.b) In general, this demonstration does not test the performance of the method in real world samples, but in the applicable and available clean quality system matrix sample (a quality system matrix in which no target analytes or interferences are present at concentrations that impact the results of a specific test method), e.g., drinking water, solids, biological tissue and air."  The statement, "such samples shall be grouped according to their origin", confuses categorization.  If a lab seeks accreditation for biological tissue matrix, is a DOC required for shellfish, plant, fish tissue, etc.?  (Assuming the lab will be analyzing various types of biological tissue.)  Extending to batch QC, is the lab required to use a shellfish CRM for shellfish samples, a fish CRM for fish samples, etc.?

TNI Response:  When all real world materials contain target analytes and/or interferences, a "representative" matrix may be used for a given test method and analyst. If the test method as defined by the combination of preparation, cleanup and determinative methods for a given biological tissue is different from the test method (preparation, cleanup and determinative method) for another biological tissue, then separate DOCs are expected. With regard to batch QC, it is highly improbable that CRMs exist for all biological tissues that could be analyzed. However, when available a CRM that matches the tissue type (e.g., shellfish, fish, etc.) should be used. A representative material may be used for laboratory control spikes as long as the material used follows all steps of the test method.  Nothing was changed in the 2009 or 2016 standards to suggest this SIR is still not relevant. The IDOC process is based on the Quality System matrix, in this case 'biological tissue'.

 

Question:  A laboratory accredited by our program asserts that the form in NELAC Chapter 5 Appendix C.2 is needed only for documentation initial demonstrations of capability and not continuing demonstrations of capability.  It cites the language from NELAC 5.5.4.2.2.d "in all cases, the appropriate forms such as the Certification Statement" and from NELAC Chapter 5 Appendix C.1 "It is the responsibility of the laboratory to document that other approaches to DOC are adequate."  Other language in the same appendix prescribes the use of the form, for example  C.1 "All demonstrations shall be documented through the use of the form in this appendix" and C.2 "The following certification statement shall be used to document the completion of each demonstration of capability."  I am requesting an interpretation to resolve the question, is the Chapter 5 Appendix C Certification Statement required for documentation of continuing demonstrations of capability?

TNI Response:  C.2 of Appendix C states that "The following certification statement shall be used to document the completion of each demonstration of capability" This statement refers only to the demonstration of capability, not continuing demonstrations of capability. The laboratory may choose to use the form to document continuing demonstrations, but it is not required.  The form was eliminated in the 2009 standard.  Rather, the standard requires documentation. The SIR is obsolete.

 

Question:  A laboratory in our program states that it is using "marginal exceedences" as part of its evaluation criteria for determining initial demonstrations of capability.  The question is "Is the use of 'marginal exceedences' as described for evaluation of laboratory control samples also allowed for the evaluation of data associated with initial demonstrations of capability?

TNI Response:  The TNI Standard requires that all analytes meet the corresponding acceptance criteria for precision and accuracy stated in the method (if applicable) or in laboratory-generated acceptance criteria (if there is not a reference method with established mandatory criteria) for an Initial Demonstration of Capability (IDOC) prior to the analysis of actual samples. If any one of the analytes does not meet the acceptance criteria, the performance is unacceptable for that analyte.