Combined Interpretations of the 2003, 2009, and 2016 Standards that apply to Volume 1 of the 2016 TNI Standard
MODULE 1: PROFICIENCY TESTING REQUIREMENTS
Section: Analysis Date
Question: Please clarify the use of "analysis date" in V1M1, section 4.2.1 a) for successive PT samples. The standard states that the analysis date is to be at least 5 months apart and no longer than 7 months apart. TNI defines "analysis date" as the "calendar date of analysis" in the "Terms and Definitions" section. So, if a PT sample is analyzed on March 15, 2011, is the period anytime between August 2011 and October 2011 (5 - 7 months) acceptable, or, must one use the period August 15, 2011 to October 15, 2011 for the next PT sample?
TNI Response: Analysis date was removed from the 2016 standard. The SIR is obsolete.
Question: There is a discrepancy between these two sections. V1M1 6.1 b) says 15 days between analysis dates for successive PTs for corrective action. V2M2 8.2 c) still uses the closing date of the previous study.
TNI Response: The 2016 standard does not discuss PTs for corrective action, but instead refers to corrective action in a general sense and references Module 2. The SIR is obsolete.
Section: Module 4 - 1.5.4 Evaluation of Selectivity
Question: Since PTs are supposed to be treated like "real environmental samples", must laboratories perform second column confirmation for "hits" in PT samples analyzed by GC methods? Or, would a PT sample be considered "a positive result detected on a sample from a location that has been previously tested by the laboratory" and therefore 2nd column confirmation is not required?
TNI Response: The 2003 NELAC Standard (Chapter 5, Appendix D.1.5) and the 2009/2016 TNI Standard (V1M4 1.5.4) require the laboratory to perform confirmations according to the method. The approved methods in Standard Methods for the Examination of Water and Wastewater and the applicable U.S. EPA methods require confirmation on "unfamiliar samples." A PT sample (by design, a sample with unknown composition) is a sample that is "unfamiliar" to the laboratory and therefore requires confirmation per method requirements.
Section: Volume 3 - 5.4.3 Supplemental PT Studies
Question: For years we have been ordering corrective action supplemental studies for PCB’s by asking for specific aroclors (that were missed in the original PT sample) and have been allowed to do so. Recently our provider could not fill an order and I went to a different provider. They told me that I could not specify an arochlor for a supplemental study. When I inquired about why I could not do so they told me that I should talk to someone at the LDEQ and they would explain. Before I called them I thought that there must be something in the standard that I was over looking and I found the above citation. I talked to several people at the LDEQ, they were not aware of this citation and they seemed to be easy persuaded either way. My interpretation of the standard is that we should have never been allowed to specify aroclors for supplemental studies. If this is true then I seem like a big dilemma, because I have not been able to find a single person who already knew about this and I have talked to a lot of people. We are trying to do the right thing, but we are getting mixed signals and no one seem to be on the same page. There is a specific exception for PCB’s, but it is vague and no one is interpreting it the same way. What are we supposed to do?
TNI Response: The PCB group is the exception. A laboratory does not need to specify the specific Arochlor and should not specify a specific Arochlor because a component of challenge of the PCB Group is both qualitative and quantitative detection. In other words, the lab must report the correct quantitative value for a specific Arochlor but also be able to report non- detects for the other Arochlors. The 2016 standard has a significant rewrite and specifically mentions aroclors and microbiology. However, the difference between a supplemental PT needed for quantitative vs. qualitative failures was not fully addressed for analyte groups.
Section: Volume 3, 5.9.3 Evaluation of Individual Participant Results
Question: The result for EDB of <0.500ug/L was scored "not acceptable", against the true value of 0.299ug/L and limits of 0.179-0.419ug/L. This result is not identified as consideration for unacceptable criteria. We disagree and feel that this result should be scored acceptable. 0.299ug/L is less than 0.500ug/L.
TNI Response: Based upon current acceptance criteria, the lab result for the analyte provided in the problem statement was correctly scored as not acceptable. The FoPT tables include a footnote that states, "Proficiency Testing Reporting Limits (PTRLs) are provided as guidance to laboratories analyzing NELAC PT samples. These levels are the lowest acceptable results that could be obtained from the lowest spike level for each analyte. The laboratory should report any positive result down to the PTRL. It is recognized that in some cases (especially for analytes that typically exhibit low recover) that PTRL may be below the standard laboratory reporting limit. However, the laboratory should use a method that is sensitive enough to generate results at the PTRL shown..." The laboratory should be aware of and take into account the corresponding PTRL for each analyte before reporting any PT results. The < value would be valid under the 2009 standard. The 2016 standard reintroduces PTRLs, and this the SIR is still valid for 2016. There are significant differences between the 2003, 2009 and 2016 standards.
Question: Based upon a question from a customer I checked the FOT tables and NELAC Chapter 2 and I can’t find a requirement for evaluation of “less than” (<) values. This was in the Criteria Document and I think was supplemented by a NELAC Board policy both or which would be invalid now. If you agree, I think the PT Board needs to implement a Policy on “less than” reporting immediately to fill the gap until the TNI Standard, which is very poor, in this area is implemented.TNI Response: The 2009 standard has explicit language regarding < values. The 2016 standard reintroduces PTRLs, and has different language regarding < values. There are significant differences between the 2003, 2009 and 2016 standards.
Section: 4.1 General Requirements
Question: I am having difficult interpreting the requirements outlined in 4.0. The main concern is with our metals department where we run methods 200.7, 6010B, 200.8, 6020. If we are analyzing a PT by all four methods and reporting all methods individually, are 200.7/6010B and 200.8/6020 being treated the same? For example, is a failure for Cobalt by 200.8 equivalent to a failure for Cobalt by 6020, even if our PT demonstrates that we passed Co by 6020? These methods have different digestions and different method requirement at the instrument level. For the 200 series we utilize a hot block digestion and the 6000 series utilizes a microwave digestion. At the instrument level, the control limits for MS/MSDs and blank spikes are different. The requirements for same-source and second-source checks are different. These are different methods. Is each metals failure for ICP a failure for all ICP methods and each ICP-MS failure a failure for all ICP-MS methods? If this is the case, are we able to only run by one method and hold the accreditation for both. The standard references FoPT, with is defined by matrix, technology/METHOD, analyte. Not just based on matrix, technology, analyte.
TNI Response: The use of the term “method” within the definition of Field of Proficiency Testing (FoPT) (2009 V1M1, 3.6) is only included to accommodate EPA’s drinking water program where PTs are required per method for the drinking water analytes referenced in the Code of Federal Regulations (CFR), specifically 40 CFR 141. The use of the term “technology” within the definition of FoPT (2009 V1M1, 3.6) only refers to the determinative analytical technology; preparative techniques/methods are not part of this definition. In addition, the Note in Section 5.1.1 of V1M1, states the following: “…If the laboratory is accredited for multiple test methods that use the same technology within a field of accreditation, the laboratory is not required to analyze a PT sample for each test method, except for fields of accreditation for the drinking water accreditation matrix for which a PT sample per test method is required…” Therefore, using the example provided, for each analyte in the same matrix, the TNI standard only requires PTs for one ICP method (200.7 or 6010B) to maintain accreditation for both ICP methods and one ICP-MS method (200.8 or 6020) to maintain accreditation for both ICP-MS methods. V1M1 of the 2016 standard was revised to include this statement "An unacceptable score for the reported test method will result in an unacceptable score for all test methods for that accreditation FoPT.
Question: A laboratory in our program has requested accreditation to measure analytes in biological tissue. The question is "If biological tissues are not listed as a matrix for the current NELAC Fields of Proficiency Testing, are proficiency tests of solid and chemical materials acceptable to demonstrate proficiency for testing biological testing?"
TNI Response: Biological tissues are not a matrix in the TNI FoPT tables, as such there would be no proficiency testing requirements for this matrix. The 2016 standard clearly indicates only analytes in FoPT tables are required.
Section: 4.2 Sample Handling, Preparation and Analysis Requirements
Question: Section 2.5 of the 2003 NELAC standard states "When analyzing a PT sample, a laboratory shall employ the same calibration, laboratory quality control and acceptance criteria, sequence of analytical steps, number of replicates and other procedures as uses when analyzing routine samples." Questions 3 through 11 of the NELAC checklist contain additional details for this section of the NELAC standard. Are these statements an official interpretation? A laboratory analyzes the PT provider companion quality control sample with the unknown PT sample. The laboratory includes all routine QC, such as blanks, LCS, etc, in the batch. In addition to using the routine QC criteria, the companion QC sample is used to determine the acceptability of the batch containing the PT. This is not a routine practice of the laboratory. Is this considered a finding versus Section 2.5 of the NELAC standard?
TNI Response: It is the consensus of the PT Committee that Questions 3-11 are appropriate interpretation of the requirements specified in Section 2.5 of the 2003 NELAC Standard. 2) It is the consensus of the PT Committee that the scenario described in the problem is a finding against Section 2.5 of the NELAC Standard. The 2009 standard (V2) contains explicit language concerning the routine analysis of PT samples. The 2016 standard (V2) removed most of the language in the 2009 standard, but Section 4.2.2 of V1M1states "PT samples shall be analyzed in accordance with the laboratory’s established standard operating procedures (SOPs) using the same quality control (QC), acceptance criteria and staff as used for the analysis of routine environmental samples."
Section: 4.3 Reporting Requirements
Question: Section 6.3 says: The Primary AB shall allow the laboratory to analyze the same PT sample using different technologies and/or multiple test methods for any FoPT. If a laboratory reports more than one test method per technology per FoPT, an unacceptable score for either test method shall result in an unacceptable score for both test methods for that FoPT. If a lab uses 2 different extraction procedures for the same analytical method (e.g. Semi-Volatile GCMS in NPW matrix using Liquid/liquid Extraction sometimes and Solid Phase extraction at other times with any of the same analytes). Would it be acceptable to run a PT sample for each technology/extraction combination as long as they stick with the "fail one/fail both" concept that is in the referenced section? It get a little muddy since the TNI standard does not really recognize preparation methods and only looks at the technology but in reality it is like 2 different test methods.
TNI Response: If PTs are analyzed using multiple preparation methods while being analyzed by a single analytical technology per an FoPT, then if one PT fails, all of the groups under that technology fail, regardless of the preparation method. The PT assessment is made by analytical technology per FoPT. The 2016 standard was revised to include this statement "An unacceptable score for the reported test method will result in an unacceptable score for all test methods for that accreditation FoPT." This topic cannot be addressed in the standard; TNI does not speak to preparation methods.
Section: 5.1-5.2 Initial and Continuing Accreditation
Question: I am confused about the PT requirements for labs doing WET analysis. The only 'true' PT is the DMRQA - but it runs longer than 45 days - which doesn't meet F.2.2 requirements. I need to know will the DMRQA be allowed and counted as a PT until such a time as the PT providers have other PTs available?
TNI Response: The 2009 standard extended the time period to 90 days. The 2016 standard removes all references to study dates for WET testing. The SIR no longer applies to the 2009 or 2016 standards. Section 5.2.2 of 2016 V1M1 for WET testing: To maintain accreditation the laboratory shall participate in one (1) WET PT study per calendar year for each accreditation FoPT that correspond to the fields of accreditation for which the laboratory is accredited. a) This requirement can be met by annual participation in the EPA DMRQA studies for WET, or b) If the laboratory is not participating in an EPA DMRQA study for WET, the closing dates of subsequent PT study samples for WET testing PT studies must be no more than fourteen (14) months apart.
Question: NELAC 2003 2.7.2 says, "For continuing accreditation, completion dates of successive proficiency rounds for a given field of proficiency testing shall be approximately six months apart. Failure to meet the semiannual schedule is regarded as a failed study." TNI V1M1 4.2.1 says, "The analysis dates of successive PT samples for the same accreditation FOPT shall be at least five months apart and no longer than seven months apart unless the PT sample is being used for corrective action to establish successful history …" There is no language to describe what happens after 7 months have passed. The sentence is missing from TNI that was in NELAC that directed or allowed the addition of a "failed study" when the semiannual requirement was not met. Is it the intent of the standard for ABs to continue treating a failure to meet the semiannual schedule as a failed study? This is a significant enforcement issue since a potential alternative seems to be in V2M2, 10.3: "The Primary AB shall revoke the accreditation of a laboratory for a FoPT when: (a) the laboratory does not participate in the PT program as required by this Standard." This penalty is too severe and problematic for what could be just a missed deadline.
TNI Response: If a laboratory fails to report a single proficiency testing result it is evaluated as "not acceptable" per V2M2 7.3 part b. If the laboratory fails to report results for 2 out of 3 proficiency testing study time frames, then the laboratory's accreditation shall be suspended per V2M2 10.1 for failing to participate in the timeframes specified in the standard.The language has been clarified in the 2016 standard. Section 5.2.3 of V1M1 states a laboratory that fails to analyze and report PT studies for a particular field of accreditation with the frequency specified in Sections 5.2.1 or 5.2.2 for which it seeks to maintain accreditation is charged with a failed PT study. The SIR is likely obsolete.