Combined Interpretations of the 2003, 2009, and 2016 Standards that apply to Volume 1 of the 2016 TNI Standard
MODULE 2: QUALITY SYSTEM GENERAL REQUIREMENTS
Section: 4.2.8 Additional Management System Requirements
Question: 188.8.131.52 calls for "periodic in-depth data monitoring". What is TNI's interpretation of "periodic"? ELAP suggested "Each calendar quarter the QAO audits 5 % or 5 data packages, whichever is more" in the DI plan template we provide to labs. However, the monitoring should be dependent upon the lab's scope (chemistry, microbiology, asbestos) and workload (number of samples analyzed). Does TNI leave it up to the lab to decide at what frequency they perform the monitoring?
TNI Response: There is no definition of periodic. The laboratory must clarify its intentions for complying with this requirement in the QAM or elsewhere. If the laboratory hasn't defined its requirements sufficiently, it could be cited for failure to comply with this section. The 2009 and 2016 standards contain the identical language. The SIR is still valid. Adding timeliness requirements may only further confuse the issue and cause unintended consequences. The Committee feels no further action need be taken.
Question: If a lab's QAM defined "signature" on technical records, reports and chain of custodies as the hand-written signature or electronic equivalent, would this meet the signature requirement for each of these documents? As we upgrade our LIMS and QC software, we have the ability to electronically sign off on chains and lab documents but want to know if this would be acceptable.
TNI Response: Electronic signatures are acceptable provided that the signature is unique to the individual. Some states may have regulatory requirements pertaining to the use of electronic signatures. The laboratory should ensure that state requirements are met.
Question: Are SOPs required for procedures not performed (e.g., “legal coc”? 184.108.40.206.1 (f) says “if required”; or subcontracting)
TNI Response: 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 220.127.116.11.1 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. This section was edited in 2009 but the SIR is still valid. There needs to be clarification that the Standard DOES NOT apply where it has not been requested or where it isn't the regulation of the land. As it relates to this SIR, a laboratory can't be expected to have a procedure for a process that it doesn't perform. This seems to be a question of clarity, so the use of a NOTE isn't exactly an issue.
Section: 4.3.1 [Document Control] General
Question: Is instrument software (or any other software) considered a controlled document? Are equipment manuals considered controlled documents?
TNI Response: Software is among the items listed in Section 4.3.1 as a document that must be controlled. Equipment manuals fall under the categories of "procedures, specifications" that are also listed in 4.3.1 as documents that form part of a laboratory's quality system. 4.2.1 and 18.104.22.168(a) also support having control over the documents, such as software and equipment manuals, that are part of a laboratory’s quality system. This language is unchanged in the 2009 and 2016 standards.
The SIR is still valid.
Section: 4.3.2 [Document Control] Document Approval and Issue
Question: 22.214.171.124(b) 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 (126.96.36.199). However, some assessors with whom I work take the position that since 4.14.1 and 4.14.5 require labs to annually review "testing activities" and conduct audits on "all elements of the management system" that these are inferred or indirect requirements to annually review all procedures. Since 188.8.131.52(b) addresses the issue directly, I take the position that it prevails over any indirect or inferred interpretation of the standard.
TNI Response: 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.
Section: 4.5.4 Subcontracting of Environmental Tests
Question: What is the documentation needed as the 'record of evidence of compliance'? Our clients are asking for our NELAP certificate, PT results, insurance certificates and QA manual. But we interpret this statement to mean having the NELAP certificate on file.
TNI Response: The requirements outlined in 4.5.1 refer to a subcontracted laboratory and the tests to be performed. They are 1) the laboratory is accredited under NELAP for the tests or 2) the laboratory meets the statutory or regulatory requirements for performing the tests. In the case of the first requirement, the NELAP Certificate that identifies the accredited test would meet the requirement. If other statutory or regulatory requirements exist, the laboratory must be prepared to provide documentation to indicate that these additional requirements have been met. However, under "Service to the Client" (4.7), the laboratory shall cooperate with the client "to monitor the laboratory's performance.... provided that the laboratory ensures confidentiality to other clients."
Section: 4.13.2 [Technical Records] Control of Records
Question: 184.108.40.206 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 Response: No. 220.127.116.11 requires observations to be recorded at the time they are made. 5.8.6(a) requires date/time of sampling to be recorded, so as to demonstrate compliance with holding times. 18.104.22.168 states the laboratory shall implement and document procedures for checking preservation. 22.214.171.124(b) (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.
Section: 4.14.1 Internal Audits
Question: One sentence reads: "Such audits shall be carried out by trained and qualified personnel who are, whenever resources permit, independent of the activity to be audited." What is the meaning of "trained and qualified" as used in the sentence? Trained and qualified in environmental matters, auditing techniques etc.?
TNI Response: Since "trained and qualified" is not defined, it would be up to the laboratory to state what their requirements are. It would be expected that the person performing the audit has a knowledge of the portion of laboratory operations that are being audited. 126.96.36.199 states that the lab management defines the minimal level of qualifications for all positions.
Question: Per Clause 4.14.1, the internal audit program shall address all elements of the management system, including the testing and/or calibration activities. It is unclear if all test methods need to be audited annually since 4.14 never uses the word "methods" but rather "areas" or "activities". Can the test methods be grouped by technology (i.e. GC/MS, ICP/MS, ICP, Spectrophotometry, Gravimetry, Meters, Titrimetry, SFIA, etc.) or does every method have to be audited annually? If grouped by technology, can different test methods within each technology be scheduled annually? The schedule beyond one year would show that tests are rotated for internal audits over time.
TNI Response: No, not every method needs to be assessed annually in the laboratory's internal audits. Yes, different methods within each technology may be assessed on an annual basis.
Section: 5.2.6 [Personnel] Additional Personnel Requirements
Question: The standard no longer contains the wording "environmental" analysis in the area of experience for sections 188.8.131.52 (b) and (c). Since it now states "such analysis" does this pertain to any type of laboratory experience in chemical, physical or environmental sciences (not just environmental)?
The terms "such analysis" indicates that the technical manager shall have experience in the fields of accreditation for which the laboratory is seeking accreditation. The experience required is of environmental analysis in the first question, and environmental microbiological analysis in the second. In both cases, the Standard requires that the analyses performed which would qualify as experience are those that would be performed by the laboratory at which a person would be the technical manager.
TNI Response: With respect to the wording about experience in 184.108.40.206, paragraph (a), sentence number one states "...and at least two (2) years of experience in the environmental analysis of representative inorganic and organic analytes for which the laboratory seeks or maintains accreditation." Paragraph (b) in sentence 2 states... “In addition, such a person shall have at least two (2) years of experience performing such analysis.”
Question #1: What is the difference between "..experience in the environmental analysis of..." , as stated in paragraph a and "...experience performing such analysis", as stated in paragraph b.
Question #2: Relating to the interpretation of "representative organic and inorganic analytes".... to what degree does methodology/technology coming in to play. Can the word "representative" be better defined? We do not find anywhere in the document that requires experience in multiple technologies. For example, if the director has experience with Analyte A using an automated inorganic method (such as segmented flow) and experience with Analyte B using a conventional wet inorganic method (such as titration) but the lab runs analyte A wet and analyte B automated, would this person have the requisite experience in that area?
TNI Response: Question 1 - There is no difference in the meaning of the wording of the two paragraphs. Each refers to two years' experience in the analysis of samples (not oversight/management of sample analysis). Question 2 - Representative - exemplifying a group or kind; typical: a representative selection of analytical methods. A Technical Director must have experience in the typical methods/technologies used by the laboratory.
Question: Please clarify 16 hours of microbiology and biology. Is it 16 hours combined total of microbiology and biology in 220.127.116.11(c)? Is it 16 hours of microbiology and 16 hours of biology 32 hours total?
TNI Response: The requirement is for a combined minimum 16 hours of microbiology and biology, not for 16 hours of each.
Question: 18.104.22.168(f) reads: Any technical manager of an accredited environmental laboratory engaged in the examination of radon in air shall have at least an associate’s degree or two (2) years of college and one (1) year of experience in radiation measurements, including at least one (1) year of experience in the measurement of radon and/or radon progeny. The list of requirements has no separating punctuation. Please clarify whether the intent is to have one of the two education options, and then experience regardless of education.
TNI Response: Yes, the requirement is to have one of the two education options in addition to the requisite year of experience in the measurement of radon.
Section: 5.4.6 [Environmental Methods and Method Validation] Estimation of Analytical Uncertainty
Question: Please explain what types of procedures for estimating uncertainty of measurements. I am not sure which area you mean.
TNI Response: Section 5.4.6 has created some confusion. Please note that as a laboratory it is impossible for you to calculate "Total Uncertainty" unless you are given all of the additional pieces from external sources to the lab itself. This section requires a laboratory to have a procedure in place, so that if requested by a client it could be determined. The key language is "Quality control measurement data may be used to determine analytical uncertainty." For example, a comparison of CCV data and LCS data could lead to an estimate of the uncertainty caused by the preparation process. A similar comparison between LCS data and MS data could lead to an estimate of the uncertainty introduced by the sample matrix. Organizations such as A2LA and the Department of the Navy have developed tools to aid a laboratory in accomplishing this task. This section was rewritten in the 2009 (and 2016) standards to state "Quality control measurement data may be used to determine analytical uncertainty." This definition was also added: "Analytical Uncertainty: A subset of Measurement Uncertainty that includes all laboratory activities performed as part of the analysis." The Committee doesn't intend to reply with a how-to document. Note that radiological requirements are well defined and are addressed in Module 6, and may also be addressed by WET methods
Section: 5.5 Calibration Requirements
Question: 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 Response: There is nothing stated in 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 are maintained, and any other requirements for records and records maintenance are met, this should be allowed.
Question: Does the requirement in 5.5.8 to indicate the status of calibration apply to devices such as a TCLP tumbler? Although we check the rotational rate monthly, there does not seem to be any adjustment on this device. Some support equipment has no "calibration" and would seem to be exempt from this regulation.
TNI Response: The cited section is preceded by "Whenever practicable". If a piece of support equipment does not require a calibration, it cannot require a notification of calibration status. It may, however, have an indication of the verification of its effectiveness (e.g., such as a date when the number of revolutions per minute on a TCLP tumbler was verified).
Section: 22.214.171.124 [Calibration Requirements] Support Equipment
Question: How encompassing is the universe of “volumetric measuring devices” needing quarterly checks for accuracy? Specifically, do graduated cylinders, glass to-deliver pipets, and other garden-variety glassware, which are not Class A, need to be checked quarterly?
TNI Response: Yes. Graduated cylinders, glass to-deliver pipets, and other garden-variety glassware, which are not Class A, must be checked quarterly.
Question: The standard states "Volumetric dispensing devices (except Class A glassware and Glass microliter syringes) shall be checked for accuracy on a quarterly basis." Would class A plasticware be considered the same as Class A glassware ie - you do not need to check it on a quarterly basis? Or would Class A plastic ware be considered the same as non-class A labware? The same question for V1M5 section 126.96.36.199 iii.2. "equipment such as filter funnels, bottles, non-Class A glassware, and other containers with volumetric markings (including sample analysis vessels) shall be verified once per lot prior to first use. This verification may be volumetric or gravimetric." Would you need to check Class A plasticware once per lot?
TNI Response: Plasticware is not glassware. Any volumetric dispensing devices that are not Class A glassware or glass microliter syringes must be checked for accuracy on a quarterly basis.
Question: Does the NIST traceable reference, in this case a thermometer that is sent out annually to an accredited company for verification, as well as the laboratory support equipment which is verified against this thermometer, also need to be calibrated by that company over the range of use?
TNI Response: A NIST-traceable reference sent out annually to an accredited company for verification or calibration is to be verified or calibrated over its entire range of use. Laboratory support equipment verified or calibrated in the laboratory against the NIST-traceable reference is to be verified or calibrated over its entire range of use. This section was revised in the 2016 standard to allow a single point verification "if the temperature measuring device is used over a range of 10°C or less." This is obsolete and can be removed from web when 2009 Standard is no longer in use.
Question: This section requires support equipment to be calibrated or verified annually with references "bracketing the range of use". The 2003 NELAC standard had comparable language requiring calibration or verification "over the entire range of use". Under the 2003 standard, an exception was permitted allowing the use of a single point calibration for narrow range use thermometers, such as those used for sample storage (>0-6C), BOD (20+/-1C) and micro incubators (35+/-0.5C and 44.5+/-0.2C), drying ovens (103C-105C), etc. However, the same exception has not been extrended to the 2009 TNI standard requirement. As a result, labs are being cited for not performing bracketing checks for these thermometers. Although the AB for the state where this issue developed allows the use of a temperature at or below and at or above the boundary of the range of use, the requirement still requires the lab to take the equipment out of normal use and re-adjust the settings multiple times. The process provides data that is probably less reliable than a single point check and requires significantly more time to perform. For example, a single point check in the range of 44.3-44.5 C for a fecal incubator would seem to be better data than a check around 40C and a second around 50C.
TNI Response: An exemption for narrow range use thermometers is not described in the 2003 NELAC Standard and historical data does not provide that an exemption was made on an organizational level. The use of a single point calibration/verification check for the narrow use range thermometers exemption is not described in the 2009 TNI Standard. This section was revised in the 2016 standard to allow a single point verification "if the temperature measuring device is used over a range of 10°C or less." The SIR is obsolete and can be removed from web when 2009 Standard is no longer in use.
Question: This section requires verification of volumes of volumetric dispensing devices (except Class A Glassware) if quantitative results are dependent on their accuracy. Historically, this section has been interpreted to include disposable pipettes and plastic tubes used for measuring sample volumes or final volumes after digestion. Section 188.8.131.52.e appears to require quarterly checks of these devices. Quarterly checks seem excessive when the items are one use items. Once per lot number seems more reasonable and would be similar to receiving a certificate from the manufacturer about the accuracy of a particular lot number.
TNI Response: A verification of one pipette or tube per lot would meet the requirements.
Question: Section 184.108.40.206(e) states, "Volumetric dispensing devices (except Class A glassware and Glass microliter syringes) shall be checked for accuracy on a quarterly basis." Our laboratory analyzes VOCs in air and uses gas tight syringes up to 100 mL to prepare gas standards. We are unsure of whether or not we must complete quarterly checks on these syringes. We're hesitant about using DI water to perform the quarterly checks on these syringes because they're used for preparing gas standards and we're unsure if moisture in the syringe would affect standard preparation. We're also unaware of how we could complete the quarterly checks using air. Our syringe vendor only offers a verification certificate for newly purchased syringes. For these reasons, it may be impractical to complete quarterly checks. As I understand it, glass microliter syringes do not require quarterly checks because they deliver such a small volume that a quarterly check would be impractical. Knowing this, if our 100 mL gastight syringes are similar in form (and from the same vendor) as our glass microliter syringes, would they require quarterly checks or not? At a minimum is there any documentation we'd have to have on file for the syringes?
TNI Response: If the syringe in question is neither Class A nor a glass microliter syringe, then it must be checked for accuracy on a quarterly basis. The laboratory must have documentation on file of this quarterly check.
Section: 220.127.116.11 [Measurement Traceability] Reference Standards
Question: I'm trying to determine if the weight sets used to verify balances prior to use MUST be Class 1.
TNI Response: A laboratory may use any class to verify the balance if the weights are traceable to a national standard. A Class 1 (or "S") weight is normally considered a reference standard, but may be used as a working standard. If the laboratory has designated the weight as a reference standard, the weight may only be used for calibration (i.e. calibrating/checking working standards). Standards that are used for daily calibrations (18.104.22.168) must be traceable to a national standard. The Class1 or “S” weights can be used to verify the working standards, since these are traceable to NIST.
Section: 22.214.171.124 [Measurement Traceability] Documentation and Labeling of Standards, Reagents, and Reference Materials
Question: For subsection (a), I would like an interpretation of the requirement to obtain the manufacturer's Certificate of Analysis for reagents. Does this mean just "ready-made" reagents (e.g. the color reagent for a test) or does this also include pure chemicals (e.g. a bottle of sodium chloride crystals)?
TNI Response: The standard requires that Certificates of Analysis be obtained for all reagents. This does not mean that the C of A is automatically supplied. In some cases, you may need to request such information from a manufacturer. This includes both "ready-made" and pure (neat) chemicals.
Question: This section requires the lab to retain records of the standard or reagent manufacturer's Certificates of Analysis. One of our largest standard manufacturers recently stopped automatically sending hard copies of the C of A with the material, stating that it can be accessed electronically from their website. The manufacturer says an advantage of this, among other things, is "immediate accessibility for audits". My question is if hard copy of the C of A onsite at the lab is strictly required, or if access to the electronic copy "on-demand" is sufficient.
TNI Response: The laboratory must maintain copies of the Certificates of Analysis (CoAs), whether in hard copy or electronic format, in accordance with the lab's records and document control procedures and as required by the TNI Standard. The laboratory must maintain and control all records used to document lab activities, including CoAs, and all records must be made available to the accreditation body. The laboratory must retain all records (hard copy or electronic) for a minimum of five years (V1M2, section 4.13.3), and labs must incorporate procedures to maintain CoA from manufactures that do not have the same retention schedule for electronic CoAs.
Question: My question is about documentation and traceability of consumables. Are environmental labs required to maintain records (i.e., Certificate of Analysis, storage, date of receipt, etc.) for such consumables as carrier gasses used for Mass Spec or Spec type instrumentation?
TNI Response: 126.96.36.199 requires documentation for "standards, reagents, reference materials, and media.” Carrier gasses are not referenced within this section. However, a carrier gas is a laboratory consumable material that affects the quality of tests and is subject to the policy and procedure requirements described in 4.6.
Question: Assuming that we have a working definition for reagents, does the word "prepared" in 188.8.131.52(d) refer only to standards or all three (standards, reference materials and reagents)? Assuming the latter, see the discussion below for the actual question). Prepared reagents are readily defined as reagents that are prepared in the lab by modifying (diluting, mixing, etc.) one or more precursor reagents or standards. However there is some ambiguity concerning the term “container.” Suppose I make 200 ml of a reagent stock, say the Ammonium Molybdate reagent used in total phosphorus analysis that is stored in a lab refrigerator. Every time we perform a TP run, a small amount of this reagent is poured into a second container, a removable, plastic reagent well that is part of our discrete analyzer’s autosampler. At the end of the day, this reagent is not completely used up, and to minimize waste, we cap the removable plastic well and store it in the refrigerator overnight. It is refilled the following day for the next day’s analysis. Since the reagent stock was prepared only once, it would be assigned a single, unique serial number. The mere act of pouring some of this reagent into a second container should not (logically) require one to generate a second serial number. To summarize the question, is only one unique serial number needed for each contiguous preparation, regardless of the number of containers in which the reagent might be stored? i.e., Is this description of unique identifiers for prepared reagents consistent with the meaning and intent of 184.108.40.206 (d)?
TNI Response: The use of the reagent at analysis requires that all data necessary for the historical reconstruction of the data be available (see 4.13.3 f). Somewhere with the analytical batch, reference must be made to the unique serial number of this reagent. A new serial number need not be created due to the act of pouring the reagent from one container to another. The unique serial number is created at a point in time when the reagent, standard or material is made in the lab. If no changes are made, then a new number need not be created. The act of removing the container from its specific location on the instrument requires that the container be labeled with the reagent's unique identifier in order to comply with the traceability requirement of 220.127.116.11 c.
Section: 5.8.5 [Handling Samples and Test Items] Additional Requirements - Documentation
Question: Do labs have to uniquely identify sample containers when received at the lab?
TNI Response: The laboratory shall assign a unique identifier to each sample received. The laboratory shall use a system for recording how it uniquely identifies multiple containers of the same sample. The system must be able to identify the sample container from which the analytical result was obtained.
Section: 5.8.6 [Handling Samples and Test Items] Sample Acceptance
Question: Is the sample acceptance plan required to be communicated to clients at any particular frequency, i.e. annually?
TNI Response: 18.104.22.168.2 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. This sentence is not in the 2009 or 2016 standards. The policy still exists, but not the requirement to make it available to the client. The SIR is obsolete and can be removed from web when 2003 Standard is no longer in use
Section: 5.8.8 [Handling Samples and Test Items] - Legal Chain of Custody Protocols
Question: We needed samples of drinking water to be tested for lead. I was disturbed to see a lab did not have a chain of custody form. I was concerned that there was an unsigned gap in the chain of custody when samples were delivered by FedEx courier to a lab nearby. The question is: isn't a complete continuous, signed Chain of Custody form required so the sample could be accounted for specifically by a signed individual?
TNI Response: A complete, continuous Chain of Custody form is not required for samples, unless otherwise specified by the client. Note that 5.8 differentiates between sample handling and tracking and legal chain of custody protocols. 5.8 requires that a record keeping system allow historical reconstruction of all laboratory activities. A laboratory that does not record the receipt of samples by a specified individual is not compliant with this aspect of the standard.
Section: 5.10.2 Test Reports
Question: Regarding test reports, is it required that they list the limit of detection with relation to the limit of quantitation? The standard states that the level of uncertainty should be included, but does that mean that the LOD and LOQ must be expressly included and with relation to each other?
TNI Response: The Standard does not require that the relationship between the limit of detection and limit of quantitation be listed on the test report, with or without regard to any estimate of uncertainty.
Section: 5.10.11 [Reporting the Results] Additional Requirements
Question: Our question for TNI concerns the documentation of the laboratory’s scope of accreditation in the test report. In this situation, our laboratory is licensed for a small number of tests in the State of Minnesota, which is adopting the NELAC Standard. Our laboratory is licensed for a full scope of parameters in the State of Arizona, a non-NELAC state. In Section 5.10, is there a requirement for qualifying data that is not included in the laboratory’s scope of accreditation? If there is a requirement (either directly or implied), how should the laboratory indicate the lack of NELAC licensure on the Arizona-only parameters in order to comply with the NELAC Standard? Is it sufficient to include a disclaimer on the cover page of the reports for Arizona-only work that indicates the data may only be used for compliance purposes in the State of Arizona and not in NELAC states?
TNI Response: Based on the standards quoted above, if the laboratory is issuing a report and the report has results that are not accredited under NELAP, you must identify those methods that do not meet the NELAP requirements (i.e., methods certified by another accrediting body). The committee cannot comment on reports that are issued for Arizona compliance purposes.
Question: In the analysis of samples for pH, our buffer range is 2 through 12. Does that mean we need to flag any values outside this calibration range? Is "J" appropriate? or a flag identified as "outside calibration range"? FYI - our analyst found a reference that states that negative values for pH are possible...and she actually got a sample like that last week from mine waste.
TNI Response: The result must be qualified to indicate that it is outside the calibration range. The use of flags to qualify data is dependent on the client requirements and state regulatory requirements. The committee cannot comment on the specific qualifier that is appropriate to use, as the use of qualifiers varies.