STANDARDS INTERPRETATION REQUEST
Section: NELAC Chapter 2

REQUEST:

Question via email to Carl Kircher, May 8, 2008:
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.

Response from Carl Kircher May 8, 2008:
I think this issue is more in the domain of the NELAP Board since the Accreditation Bodies make laboratory accreditation decisions based on the PT results. I do know that the NELAP Board is collecting all the former NELAC Board FAQ decisions, as well as the old NELAC AAC decisions / policies. The purpose, I think, is to use those decisions and policies within the auspices of TNI until the TNI PT Standard is accepted for use. I also think that the TNI Lab. Accreditation System Committee may put forth a recommendation on how AB's should handle PT results based on "less than" reported laboratory results (along with any recommendations on PT sample participation frequency). If you want my opinion as one Analytical Chemist, I can provide that opinion in a separate e-mail.

TNI FINAL RESPONSE:

(PT Board / NELAP Board, 10-11-09)

The TNI PT Board concurs with the need to define a policy, as a stop gap measure until such time as the TNI Standard Volume 3 is implemented, on the evaluation/scoring of PT results reported as "less than" (<) or zero values. This new policy will replace previous policy as outlined in the NELAC BOD Policy #16 (effective 12/14/2000) and the EPA National Standards for Water Proficiency Testing Studies Criteria Document (January 31, 2001). The drafting of a policy document on this topic by the PT Board is now underway. Once completed, this new policy document will be recommended to the Policy committee and TNI Board for adoption.

STANDARDS INTERPRETATION REQUEST
Section: 2.6

REQUEST:

1. ILAC Guide 13 in section 3.6.1.7 requires the PT provider to have procedures for dealing with small data sets that may be inappropriate for statistical evaluation. APG has protocol in place for all non-NELAC PT programs that deals with this issue. However, in the case of the NELAC PT program, APG feels strongly that since NELAC evaluation limits are regulatory and are written into State laws that we have no option but to apply the NELAC FOT requirements as written without exception regardless of sample size.

However, the A2LA auditors are requiring us to use an alternative evaluation technique based upon our own technical judgment, or prior studies on a case by case basis. While is would be simple to implement a criteria based upon professional judgment it would raise issues of objectivity. Such a procedure would lead to variability in laboratory evaluations, and be in conflict with the NELAC level playing field concept. Such practices would lead to arbitrary and inconsistent evaluations. It would furthermore transfer responsibility for setting laboratory evaluation criteria to the PT provider and removes it from the NELAC PT Board who are responsible party.

The NELAC 2003 Standard in Chapter 2 Section 2.6 says: "PT providers shall evaluate results from all PT studies using NELAC mandated acceptance criteria described in Appendix C." It continues: "The PT Board shall provide, and update as necessary, the data acceptance criteria that all providers shall use for all PT studies". Based upon this section APG believe that ILAC Guide 13 Section 3.6.1.7 is not relevant to the NELAC program until the NELAC PT Board provides the necessary acceptance criteria.

TNI FINAL RESPONSE:

(Proficiency Testing Board / NELAP Board, 10-11-09)

The TNI PT Board thinks that the acceptance criteria listed in the various Fields of Proficiency Testing Tables should be adequate to meet ILAC G13 requirements in most cases. For those analytes where the acceptance criteria are based on fixed limits or upon regression equations, these limits and criteria are based on aggregate PT data spanning several years from multiple PT providers.

Of course, the NELAP Program requires PT results to be scored acceptable or unacceptable based on these published limits. If the number of participants in the PT study is small, the acceptance limits published in the Tables still need to be used. However, since these limits are based on the aggregate scientific and statistical analyses, the TNI PT Board thinks that using these limits would satisfy ILAC G13 requirements for small data sets. The PT Provider should not have difficulty using this as a justification, and this justification should carry more tangible, defensible weight compared with any other alternatives that could be considered.

Nevertheless, there are Fields of Proficiency Testing where the acceptance limits are still based on consensus participant mean and a PT-study specific standard deviation. In these cases, the PT provider would definitely need to formulate an alternate procedure to handle small data sets. However, the TNI PT Board cannot really provide or advocate a specific protocol to use in these instances. In fact, it may be scientifically unsound to do so, since other procedures and statistical models (e.g., Lorentzian, Maxwellian, chi-squared, or Poisson, as opposed to Gaussian) may work better. In addition, the PT Provider may need to adapt or change models and procedures used to accommodate individual circumstances for a given PT study.

The TNI PT Board thinks the important thing to do is to document the preferred procedure(s) chosen (to satisfy ILAC G13), implement this procedure for the small data sets as needed, and be prepared to revise the SOP if the results do not work out as expected.

STANDARDS INTERPRETATION REQUEST
Section: 2.7.3.1 (d)

REQUEST:

"For corrective action supplemental studies, the assigned values for all analytes requested by the laboratory must not be equal to zero with the exception of the qualitative PCB group and qualitative microbiology."

For years we have been ordering corrective action supplemental studies for PCB's by asking for specific arochlors (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 arochlors 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 suppose to do?

TNI FINAL RESPONSE:

(PT Expert Committee/NELAP Board, 10-11-09)

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.

STANDARDS INTERPRETATION REQUEST
Section: Appendix B.2.1 and B.2.2

REQUEST:

3. Finally there appears to be a highly technical issue and conflict between Sections B 2.1 and B 2.2 of Appendix B in the 2003 NELAC Standard. Section B 2.1 requires the RSD of a method to be less than 50% of the RSD predicted at the Assigned Value of the sample. The NELAC regression equations predict variable standard deviations and RSD across the NELAC concentration ranges and in many instances NELAC criteria require interlaboratory evaluation limits which vary with laboratory population and concentration range. However, good method development procedures require the RSD of a method to be constant across the calibration range which in most cases is not consistent with the NELAC concentration range. The RSD of a method is controlled by the technique of the method and the variability of the instrument not by the NELAC concentration range.

The more important requirement to protect PT sample integrity is in Section B 2.2 and it requires the actual standard deviation of the verification analysis to be within 1.5 times the predicted standard deviation at the Assigned Value of the sample. If a method is capable of insuring that the sample meets the standard deviation requirement of section B 2.2 then it should be considered adequate to meet the requirements of the PT program. If the method is capable of achieving the necessary reliability in terms of meeting the standard deviation requirement of Chapter 2 Appendix B 2.2 then it is fit for use.

TNI FINAL RESPONSE:

(Proficiency Testing Board / NELAP Board, 10-11-09)

Sections B.2.1 and B.2.2 serve different purposes and are not in conflict. The purpose of B.2.1 is to ensure that each analytical method being used is precise enough to effectively detect any bias or inhomogeneity in the sample. Section B.2.2 provides the specific criteria for evaluating the homogeneity of the sample. Both sections must be followed.

STANDARDS INTERPRETATION REQUEST
Section: Appendix E.3.2.1 / Chapter 2 2.6

REQUEST:

2. A similar [to the request regarding section 2.6] but more difficult situation occurs with the evaluation of microbiological data sets. In the case of quantitative microbiology, the NELAC 2003 Standard Chapter 2 Appendix E Section 3.2.1 appears to authorize the PT provider to use alternative evaluation criteria where 20 valid data points are not available. The Appendix appears to be in direct conflict with Chapter 2 Section 2.6 noted above which clearly states that there are no exceptions. The APG procedure in this case was to supplement available interlaboratory data with internal testing data run by the same method as the laboratories. The A2LA auditor found this to be inappropriate. We do not disagree with the auditors in this instance; however, Chapter 2 Appendix E Section 3.2.1 requires any alternate procedure to be approved by the PTOB. Clearly, the responsibility to providing acceptable evaluation criteria lies with the NELAC PT Board as noted in Chapter 2 Section 2.6 and not with either the PT provider or A2LA. In an effort to get appropriate guidance from A2LA as to available acceptable alternate procedures, we requested guidance from the A2LA microbiological auditor. She provided no recommendation on alternative acceptable procedures. Similarly, we requested guidance from the statistical auditor whose comment was that other providers have procedures but that he was not allowed to provide consultation.

It appears to APG that if an alternative quantitative microbiological evaluation procedure must be approved by the PTOB that they then have an obligation to provide guidance on an acceptable proceed. However, it seems inappropriate for A2LA to accept responsibility for setting NELAC acceptance criteria when that function is vested in the NELAC PT Board by the 2003 NELAC Standard. Therefore, in order to meet the requirement of Chapter 2 Appendix E 3.2.1 alternative guidance must be provided since it is also not the responsibility of the PT provider to establish NELAC evaluation criteria.

TNI FINAL RESPONSE:

(Proficiency Testing Board / NELAP Board, 10-11-09)

The information in specific appendices, i.e. Appendix E for Microbiology, takes precedence over the information in the general standard, where conflicts exist. Therefore, Appendix E 3.2.1 must be followed and states, in the second sentence, "Sample sets of less than 20 data points may be used only with the approval of the PTOB/PTPA." The commentor needs to develop and present an option to A2LA and then work through any feedback until they have an acceptable procedure.

STANDARDS INTERPRETATION REQUEST
Section: 5.4.3.2.2 (b)

REQUEST:

The above section requires documents to be reviewed "periodically". I have interpreted this to mean that NELAC wants the documents reviewed but requires the lab to establish the frequency. NELAC further supports this position by specifically requiring data integrity procedure to be reviewed annually (5.4.2.6). However, some assessors with whom I work take the position that since 5.4.14.1 requires labs to annually review the "suitability of procedures" and 5.4.13.1 requries labs to annually conducts audits on "all elements of the quality system" that these are inferred or indirect requirements to annually review all procedures. Since 5.4.3.2.2.b addresses the issue directly, I take the position that it prevails over any indirect or inferred interpretation of the standard. Agree? Disagree?

TNI FINAL RESPONSE:

(Quality Systems Expert Committee/NELAP Board, 10-25-08)

The Quality Systems Committee sees no conflict here. The internal audits must show compliance with the laboratories policies and procedures. This is a procedural review for compliance and suitability.

The periodic review of SOPs is set by the lab and does require that technical management review current procedures. This can be done with internal method audits. If the AB finds issues that would indicate that periodically has been stretched too long, then the AB could impose a finding that would require the timeframe be shortened.

Also, support procedures can be allowed to have longer periods between review, such as when changes are needed due to a change in laboratory practice.

STANDARDS INTERPRETATION REQUEST
Section: 5.4.12.2.2

REQUEST:

This section of the standard talks about observation, data and calculations recorded at the time they are made. Currently our lab has a policy in place to mark the preservation checks for each sample separately. Example a specific sample has a pH of less 2 and chlorine result of zero. Would it be sufficient to document the pH and chlorine checks by a general statement for example "all samples extracted in the batch had a pH less than 2 and chlorine result of zero"?

TNI FINAL RESPONSE:

(NELAP Board, 12-19-08)

No. 5.4.12.2.1 requires observations to be recorded at the time they are made. 5.4.12.2.5.1 requires date/time of sampling to be recorded, so as to demonstrate compliance with holding times.

5.5.8.3.1(2) states the laboratory shall implement procedures for checking chemical preservation prior to or during sample preparation or analysis.

3(b) requires the results of these checks to be recorded.

5.5.8.3.1(d) (2) (iv) requires comments resulting from inspection for sample rejection to be linked to the laboratory ID code.

So, the lab could, for example, use a check box on a sample receipt form to indicate a sample's preservation was checked and the result was less than 2 and chlorine was zero as long as the observation was unequivocally linked to each sample checked. The lab could not simply preprint this statement on an analytical report or document preservation after-the-fact in an extraction log because doing so would not comply with requirements to record observations at the time they are made and link the results of preservation checks unequivocally with sample identification numbers.

STANDARDS INTERPRETATION REQUEST
Section: 5.5.4.1.1

REQUEST:

Are SOPs required for procedures not performed (e.g., "legal coc" 5.5.8.3.1 f) says "if required"; or subcontracting)

TNI FINAL RESPONSE:

(Quality Systems Expert Committee/NELAP Board, 10-27-08)

SOPs are not required for activities that the laboratory is not required to perform. The converse is obviously true, in that you must have an SOP if you perform, or are required to perform, these activities. The first paragraph of 5.5.4.1.1 states that SOPs must "accurately reflect all phases of current laboratory activities". Where an activity is not performed, such as legal Chain of Custody, the laboratory should not be required to have an SOP for what it doesn’t do. Compliance could be demonstrated if the lab's Quality Manual states 'We do not perform legal CoC, and will refuse any samples requiring legal CoC', although this is not mandatory.

STANDARDS INTERPRETATION REQUEST
Section: 5.5.4.2.2

REQUEST:

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.'

Q1 - 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.'

Q2 - 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?

Thank you for considering these two questions.

TNI FINAL RESPONSE:

(Quality Systems Expert Committee/NELAP Board, 10-25-08)

5.5.4.2.2.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.

STANDARDS INTERPRETATION REQUEST
Section: 5.5.4.4; 5.5.4.5; Appendix C3.3 (b)

REQUEST:

This has been passed around previously, but wasn't officially put out for interpretation, and would be good for open discussion/the forum.

non-standard methods/modification of methods

2 questions concerning mercury:

1) EPA 245.1 vs SW846 7470: SWrequires heating the standards, the EPA method doesn't. Is it acceptable to do the same for both (i.e., batch them together), and still be accredited for both methods in non-potable water? The Standard says validation is to be as extensive as necessary and C3.3b) only applies if the method was not in use prior to 7/03. If there are 20 years of at least 4 PT standards per year without a failure, the method should be sufficiently validated. This can't be left to individual state interpretation since one lab could be required to do two digestions/calibrations and other labs not, depending on where they're located. What if a lab is bidding on work in a state that allows the modification, but the home state doesn't? The real question is: Who decides if the modification is acceptable, if it has been sufficiently validated, and whether a lab can be accredited for "the method"? (especially when something is common practice)

2) Same issue with using HCL instead of H2SO4 to make the stannous chloride solution (the instrument manufacturer recommends HCl although the method says H2SO4).

TNI FINAL RESPONSE:

(Technical Assistance Committee / NELAP Board, 2-19-09)

Note: Laboratories should attempt to reconcile all differences in the interpretation of the NELAC 2003 standards and/or analytical methods with the applicable EPA Program, Regional office and/or NELAC accreditation body. The following is an opinion of the current TNI Technical Assistance Committee and NELAP Board.

The following response was obtained by the TNI Technical Assistance Committee TAC from EHSG MICE.

First off, we would like to clarify a common misnomer pertaining to SW-846 methods that is alluded to in question one. Please stress to this member that Methods 245.1 and 7470 are in fact both EPA publications. The former from the Office of Water while the latter is published by the Office of Solid Waste.

Now to answer the questions, it is recognized that historically the most common practice was to digest the calibration standards in the same manner as the samples. However, with the newer instrumentation direct calibration using an aqueous standard is now possible, so the digestion steps are no longer necessary. So, in this particular case it depends more on the instrumentation and the manufacturer's calibration requirements rather than what is specified in the method. In addition, using EPA OSW's PBMS approach any calibration format is considered acceptable as long as adequate performance data are generated. If the desired sensitivity is attainable and QC data meet the project requirements, the practice of not digesting standards should be considered acceptable. The direct calibration option we alluded to will be included in the revised mercury Methods 7470A and 7471B that are due to be published with the SW-846 Fourth Edition update, hopefully late next year.

Using this same logic, if the instrument manufacturer recommends HCl to prepare the stannous chloride solution this again would be a perfectly acceptable modification under the OSW's PBMS policy. After all the instrument manufacturer should know best what operating conditions for their equipment will generate the most reliable data.

The following response was obtained by the TNI Technical Assistance Committee TAC from EPA OSTCWA Methods.

1) SW requires heating the standards, while the EPA method doesn't. Is it acceptable to do the same for both (i.e., batch them together)? Either digesting all of the standards and QC samples for 245.1 along with 7470, or not digesting the standards and analytical QC (preparation QC like MB, LCS, MS, etc. would still be required) If there are 20 years of at least 4 PT standards per year without a failure, doesn't that show that the modification is sufficiently validated? We know of regulatory authorities that do not view this modification consistently.

* For CWA compliance monitoring - we agree that the modification has been sufficiently validated, provided validation (including QC) requirements in the method and in 40 CFR 136.6 have been met.

2) Same issue with using HCL instead of H2SO4 to make the stannous chloride solution (the instrument manufacturer recommends HCl although the method says H2SO4). In this particular case can either acid be used regardless of what the method states? Is there any indication that the change in acid would compromise the recovery of the mercury?

*Same answer for CWA; i.e., if QC requirements in the method and in part 136.6 have been met.

-----
These modifications were made long before 136.6 appeared in the CFR and, therefore, the modifications should be allowed because of their history of use. If the labs have been doing the QCS, MS, MDL, LRB, LCS, and recovery tests required by Section 9 of 245.1, and other QC tests required by the method, and have met the QC acceptance criteria, they've already met the requirements of 136.6. In that case, the modifications should be allowed and grandfathered.

STANDARDS INTERPRETATION REQUEST
Section: 5.5.5.2.2.1 (d)

REQUEST:

The section in question states:
d) All initial instrument calibrations must be verified with a standard obtained from a second manufacturer or lot if the lot can be demonstrated from the manufacturer as prepared independently from other lots. Traceability shall be to a national standard, when commercially available. Our question is, does the requirement for second source standard include calibration curves for surrogate compounds?

TNI FINAL RESPONSE:

(Quality Systems Expert Committee / NELAP Board, 10-11-09)

Surrogates are intended to provide a measure of recovery for every sample matrix (D.1.1.3.3 a). A second source check is designed to assure that the analytes of concern are being correctly identified and quantified. Since surrogates are not analytes of concern, and may be held at a constant level in a calibration curve, they are not required to be verified by a second source.

STANDARDS INTERPRETATION REQUEST
Section: 5.5.5.2.2.1 (d)

REQUEST:

My question concerns the definition of a second source standard. What input variables (analyte lot, solvent lot, balance, operator, etc) must change in order for a second lot of standard to be considered to be prepared independently? Thanks for your help.

TNI FINAL RESPONSE:

(Quality Systems Expert Committee/NELAP Board, 2-19-09)

5.5.5.2.2.1 d states that a standard obtained from a second lot may be used if the lot can be demonstrated from the manufacturer as prepared independently from other lots. In our mind, this is analogous to a preparation batch being prepared with the same process, personnel and reagents during a set timeframe. Assuming the manufacturer prepares a specific quantity of standard and declares that quantity a “lot”, another lot prepared at another time would be independent of the first. The laboratory would be expected to contact the manufacturer to verify that one lot is not the same as another.

STANDARDS INTERPRETATION REQUEST
Section: 5.5.5.5

REQUEST:

Are electronic records sufficient for instrument maintenance? If not, can the electronic records be printed and indexed periodically (perhaps monthly) to satisfy hard copy requirements? We can currently record all maintenance in our LIMS system.

TNI FINAL RESPONSE:

(Quality Systems Expert Committee/NELAP Board, 10-11-09)

There is nothing stated in 5.5.5.5 that states that records must be hard copy. If the records are maintained in a secure manner (presumably the LIMS contains audit trails and password protection), all of the items required in 5.5.5.5 are maintained, and any other requirements for records and records maintenance are met, this should be allowed.

STANDARDS INTERPRETATION REQUEST
Section: 5.5.5.10

REQUEST:

The following comments and concerns are base on actual practices observed in laboratories based on possible interpretations of the NELAC standard.

Section 5.5.5.10 begins with the statement "When an initial instrument calibration is not performed on the day of analysis, the validity of the initial calibration shall be verified prior to sample analyses by continuing instrument calibration verification with each analytical batch. The following items are essential elements of continuing instrument calibration verification:". This is a forward looking statement meaning that the pass/fail status of the CCV standard being run is evaluated only in light of it’s impact on the samples which follow the CCV standard.

Section 5.5.5.10 e) reads "If the continuing instrument calibration verification results obtained are outside established acceptance criteria, corrective actions must be performed. If routine corrective action procedures fail to produce a second consecutive (immediate) calibration verification within acceptance criteria, then either the laboratory has to demonstrate acceptable performance after corrective action with two consecutive calibration verifications, or a new initial instrument calibration must be performed."

The corrective action language in the standard only address what is necessary to proceed with analysis without recalibration. I referred to this evaluation as being "forward looking". There is no interpretation given regarding any additional considerations, or limitation on corrective actions for nonconforming CCV events where they occur in the middle or the end of a sequence that requires acceptable bracketing CCVs such as in GC analysis without the use of internal standards.

The following practices have been observed in NELAC accredited laboratories:

• A laboratory routinely will set up two consecutive CCVs during an automated sequence. If the first CCV passes, the laboratory will not evaluate the second. However if the first CCV fails and the second one passes the laboratory will report all preceding and trailing samples as being bracketed by an acceptable CCV.

• In an "attended" continuous sequence it has also been observed that a laboratory will perform instrument maintenance such as changing an inlet liner etc. in between CCVs and again treat the second passing CCV as the acceptable bracketing CCV for the preceding samples.

Comment: these practices constitute the "priming" of an instrument before running a CCV, the treatment of QC samples differently from the associated samples, and the "cherry picking" of QC that passes over QC that fails. However, there is no language in the standard that clarifies the CCV evaluation regarding their potential impact on the preceding samples.

In the above cases the laboratory has argued that the NELAC standard allows for this.

It is requested that clarification be provided regarding the impact on a failing CCV on the preceding samples during a continuing sequence where acceptable bracketing CCVs are required.

TNI FINAL RESPONSE:

(Quality Systems Expert Committee/NELAP Board, 12-19-08)

Running a second CCV in a sequence is not the intention of the standard. The practice of running two CCVs routinely would require that the laboratory evaluate each of them on every occasion. There must be a form of corrective action (i.e., instrument maintenance) prior to the second CCV being evaluated. Since no corrective action is being taken between the two CCVs, the laboratory is failing the requirement in 5.5.5.10 e of performing routine corrective action (unless it can be documented that something occurred in the first CCV, such as poor sample introduction, that did not occur in the second CCV), and cannot use the second CCV to alleviate the failing of the first.

STANDARDS INTERPRETATION REQUEST
Section: 5.5.8.3.1

REQUEST:

The test method specifies thermal preservation at a temperature of 4 C. The samples are hand delivered on ice to the lab on the same day as they are taken. They are received on ice, but the samples taken at the end of the sampling route may have only been chilling 15 - 30 mintues and may not be at or below 6 C as specified by the test method. The NELAC sample receipt protocol in 5.5.8.3.1 states that such samples may not meet the temperature criteria and that in such cases, the samples shall be considered acceptable. The question has arisen as to whether under these circumstances, documentation of receipt on ice is sufficient to meet the method and preservation documentation as the protocol implies, or does the actual sample receipt temperature still have to be recorded? What is the purpose of recording a temperature that is clearly acknowledged as likely to be outside the acceptance criteria if the sample is clearly deemed acceptable as described above. Would recording such temperature data actually make the data more susceptible to challenge by a third party?

TNI FINAL RESPONSE:

(Quality System Expert Committee/NELAP Board, 10-11-09)

The allowance for samples exceeding temperature requirements when delivered shortly after sampling does not alleviate the requirement to record a temperature, even in the presence of ice. No, documentation of receipt on ice is not sufficient to meet method requirements, since methods require the temperature upon receipt. Methods and regulations require that the temperature upon receipt be recorded, regardless of whether that information is in compliance or out of compliance. This should not make the data more susceptible to challenge, since it is clearly allowed as an exception.

STANDARDS INTERPRETATION REQUEST
Section: 5.5.8.3.2

REQUEST:

Is the sample acceptance plan required to be communicated to clients at any particulary frequency, i.e. annually?

TNI FINAL RESPONSE:

(Quality Systems Expert Committee / NELAP Board, 10-11-09)

5.5.8.3.2 states that the "sample acceptance policy shall be made available to sample collection personnel." The introduction included in 5.5.8 states "the following are essential to ensure the validity of the laboratory's data," which would mean that the laboratory can't invoke 5.1.2, which states "When a laboratory does not undertake one or more of the activities covered by this Standard, such as sampling and the design/development of new methods, the requirements of those clauses do not apply" to avoid having such a policy. However, the Standard makes no mention of any period under which the acceptance policy must be communicated to clients.

STANDARDS INTERPRETATION REQUEST
Section: 5.5.10.2 (i)

REQUEST:

The standard states the report should note whether the sample result was calculated on a wet weight or a dry weight basis. The narrative that accompanies every analytical report out of our laboratory states "all sample results are reported on an "as-received" basis unless otherwise noted". My question is why does the report have to note whether it is dry or wet weight a second time, when we have already noted "as-received"?

TNI FINAL RESPONSE:

(NELAP Board, 12-19-08)

5.5.10.2(i) requires identifying whether data are calculated on a dry weight or wet weight basis Recording sample result as being calculated on the basis of 'as received' does not indicate wet or dry weight basis. As or more importantly, identifying results as having been calculated on an 'as received' basis would not comply with requirements in 5.5.10.1 to report results unambiguously. The laboratory could have a statement: "All results are wet weight unless otherwise noted."

STANDARDS INTERPRETATION REQUEST
Section: Appendix C.1

REQUEST:

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.

I appreciate your time with this question.

TNI FINAL RESPONSE:

(Quality Systems Expert Committee/NELAP Board, 10-25-08)

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.

STANDARDS INTERPRETATION REQUEST
Section: Appendix C.1 (e)

REQUEST:

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 FINAL RESPONSE:

(Technical Assistance Committee / NELAP Board, 2/19/09)

Note: Laboratories should attempt to reconcile all differences in the interpretation of the NELAC 2003 standards and/or analytical methods with the applicable EPA Program, Regional Office and/or NELAC accreditation body. The following is an opinion of the current TNI Technical Assistance Committee and NELAP Board.

In reviewing EPA 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, 1.e.

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.

STANDARDS INTERPRETATION REQUEST
Section: Appendix C.3.1 (b)

REQUEST:

It is felt that the LOD validation procedure in the 2003 NELAC Standard is ambiguous and can result in two different interpretations. By using the relevant standards (C.3.1.b, D.1.2.1.a) as well as definitions in the glossary especially for terms such as a quality system matrix, you can construe two different procedures.
One interpretation is that the LOD must be determined only in the matrix of the sample. In other words, if a lab is analyzing wastewater effluent samples, the LOD must be validated only in a wastewater effluent matrix. Not only is this not practical but not possible for many analytes.
This is a challenge to the practical and second interpretation which allows for the LOD to be validated in a reagent water matrix.
As someone who is engaged in quality assurance work, whenever an alternative interpretation is brought to me, I must evaluate objectively all viewpoints and I feel there is merit to the alternative argument. With respect to the two choices, we like to hear from you as to which choice is right and as stated we like to alert you that they may be an ambiguity issue with the LOD procedure.

TNI FINAL RESPONSE:

(Quality Systems Committee / NELAP Board, 12-19-08)

Reagent water (however named) is accepted as the quality systems matrix used for the determination of LOD for wastewater analyses.

STANDARDS INTERPRETATION REQUEST
Section: Appendix D.1.1.2.1

REQUEST:

Can control limits include 0? Marginal exceedances must be random. If control limits don't include 0, poor performing analytes will consistently be marginal exceedances.

Same question for demonstration of capability.

TNI FINAL RESPONSE:

(Quality Systems Expert Committee/NELAP Board, 10-25-08)

The laboratory would have to demonstrate how its data can meet all other aspects of the method and still generate control limits that include a 0% recovery. However, there is no restriction on control limits using 0 - look at PT criteria for soil to see examples of this occurring.

As for marginal exceedances, there's no such thing as a "consistent marginal exceedance", since they are required to be random. Consistent means that there is something wrong in the process or the method just doesn’t work for that analyte.

STANDARDS INTERPRETATION REQUEST
Section: Appendix D.1.1.3.1 (c)

REQUEST:

A recent finding our laboratory got was "The laboratory does not include all target analytes in the matrix spike mixture over a 2-year period (EPA 8082)."

We feel that some auditing entities may be overreaching in their interpretation of this section. Our response follows:

EPA 8082 describes the analysis of PCBs in environmental samples. PCBs can be reported as Aroclors or as individual congeners; ENCO reports PCBs as Aroclors.

Section 7.1.2 of the method states that "Aroclor 1016/1260 mixture may be an appropriate choice for spiking" because these two in combination represent all PCBs. Section 8.4 of the method states that "If samples are not expected to contain target analytes, laboratories should use a matrix spike and matrix spike duplicate pair, spiked with the Aroclor 1016/1260 mixture."

Furthermore, the NELAC standard states in Appendix D, section 1.1.2.1 (c), referring to PCBs, that "the spike should be chosen that represents the chemistries and elution patterns of the components to be reported."

Aroclors are a special situation in that they are not a compound, but rather a formulation of different proportions of PCBs.

TNI FINAL RESPONSE:

(Quality Systems Expert Committee/NELAP Board, 10-25-08)

Under D.1.1.3.c Composition
The components to be spiked SHALL be as specified by the mandated test method. 8082 specifically says

7.1.2 'Such samples should contain or be spiked with the compounds of interest in order to determine the percent recovery and the limit of detection for that sample type (see Chapter One). When other materials are not available and spiked samples are used, they should be spiked with the analytes of interest, either specific Aroclors or PCB congeners. When the presence of specific Aroclors is not anticipated, the Aroclor 1016/1260 mixture may be an appropriate choice for spiking.'

and

8.4.1 Documenting the effect of the matrix should include the analysis of at least one matrix spike and one duplicate unspiked sample or one matrix spike/matrix spike duplicate pair. The decision on whether to prepare and analyze duplicate samples or a matrix spike/matrix spike duplicate must be based on a knowledge of the samples in the sample batch. If samples are not expected to contain target analytes, laboratories should use a matrix spike and matrix spike duplicate pair, spiked with the Aroclor 1016/1260 mixture. However, when specific Aroclors are known to be present or expected in samples, the specific Aroclors should be used for spiking. If samples are expected to contain target analytes, then laboratories may use one matrix spike and a duplicate analysis of an unspiked field sample.

The method requires analytes that you may expect in samples. This would mean spike all analytes over a two year period and if you're doing projects of known contamination you have to spike with those the known contaminant. If they can demonstrate that they’ve never seen any PCBs in their laboratory, a case could be made that they could just use 1016/1260 as a spiking mixture. If that can't be demonstrated, then all Aroclors must be spiked over the course of 2 years.

STANDARDS INTERPRETATION REQUEST
Section: Appendix D.1.2.1 (c)

REQUEST:

Our laboratory was recently cited with "The laboratory has not established procedures to relate LOD's with Limits of Quantitation (LOQ's) (EPA 200.8, 300.0, 6020, 9056)."

I must be missing something here, or perhaps an expectation is being created by this standard, which is a favorite deficiency for auditors.

The LOD (which is not clearly defined in the NELAC standard) is interpreted by our company to be equivalent to the MDL. The MDL is derived from an MDL study following the guidance in 40CFR136.

The LOQ is interpreted by our company to be lowest concentration that can be reliably and accurately reported, and it is required that it be encompassed in the calibration curve. Typically the low point of the calibration curve is equal to the LOQ when adjusted for sample preparation factors.

In this context, the LOD and the LOQ are numbers that are derived independently, and the only requirement is that the LOD be equal to or less than the LOQ. However, auditors are implying that there should be a fixed factor (or range, such as 1-10) separating the LOD and the LOQ. In our laboratory, metals by ICP-MS have ratios of LOQ/LOD that range from 1.4 to 100. In my 20+ years in environmental laboratories, I have seen LOQ/LOD ratios that are all over the place.

Is the standard giving me permission to adjust MDLs upward, provided that they are supported by MDL studies, so that the LOD is withing a fixed factor of the LOQ? This would be convenient, because the LOD would not change from year to year. Our clients would be very appreciative of invariable LODs. The question is, is this something that NELAC supports?

I would like to see some clarification on this standard, because the way it is written, it seems to create the perception that we are missing something.

TNI FINAL RESPONSE:

Quality Systems Expert Committee/NELAP Board, 10-x-08: Since the lab is using the low standard as their LOQ, and the 40CFR value as their LOD, there won’t be a mathematical ratio between the two. If the lab can point to a statement in their SOPs or Quality Manual that the LOQ is greater than the LOD, they would be in compliance.

STANDARDS INTERPRETATION REQUEST
Section: Appendix D.1.6 (a)

REQUEST:

Not sure if this is the applicable section for this question. This question has to do with method 524.2 section 11.2.1 which talks about desorb time of about 4 minutes. If DOC and MDL studies show that a 2 minutes desorb time achieves equal or greater method performance as the 4 minute desorb time, will this method modification meet NELAC requirements for drinking water volatile analysis.

TNI FINAL RESPONSE:

(Technical Assistance Committee / NELAP Board, 2-19-09)

Note: Laboratories should attempt to reconcile all differences in the interpretation of the NELAC 2003 standards and/or analytical methods with the applicable EPA Program, Regional office and/or NELAC accreditation body. The following is an opinion of the current TNI Technical Assistance Committee and NELAP Board.

The following is an excerpt of an email regarding the allowable changes to purge time for EPA Method 524.2, Rev. 4.1, received in 11/07 by one State program from EPA Cincinnati:

The statement in the method of "about 4 minutes" was to avoid issues with people demanding that desorb time be exactly 4.00000 minutes. It should be interpreted as times that could be rounded to 4, such as 3.5 to 4.4. It was not meant to permit people to have drastically shorter times.

Modification to methods should be confirmed with the applicable EPA ATP program and Accreditation Program. DOC and MDL studies alone do not necessarily meet the requirements of an allowable method modification. For further consideration please refer to the 40 CFR, Part 141, Expedited Approval of Alternative Test Procedures for the Analysis of Contaminants Under the Safe Drinking Water Act; Analysis and Sampling Procedures, Federal Register / Vol. 73, No. 107 / Tuesday, June 3, 2008 / Rules and Regulations.

During the TNI Laboratory Forum Conference in Miami, scheduled for January 2009, the Assessment Forum (1/13/09) will include topics on What is a Non-Standard Method? When do Standard Methods become non-standard modified methods?

STANDARDS INTERPRETATION REQUEST
Section: Appendix D.3.1

REQUEST:

In Standard Methods [SM9020] there is a requirement to do at least one positive sample verification monthly, in some cases 10% etc. Question: What if you do not have any positive samples, should you do a positive verification anyway? I see that for DW (source) even if you do not have any positive samples, a positive verification check is to be done quarterly. How about the other type of waters? For example to check any false negatives? Frequency?

TNI FINAL RESPONSE:

(Quality Systems Expert Committee/ NELAP Board, 10-11-09)

Questions involving specific methods should be directed to the writer of the method. For information about the requirements in the NELAC Standard, see D.3.1 b. The requirement for positive controls exists so that the lab can demonstrate that IT isn't the reason there are no positives, i.e., it isn’t doing something that causes no growth.