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


MODULE 4: CHEMISTRY TECHNICAL REQUIREMENTS
Section: 1.7.1.1

Question:  ICVs have historically been treated as CCVs, in that high-biased failures and samples with no target compounds did not require reanalysis. It has been noted in a previous audit that this is not acceptable even though there would be qualifications on the final client report. Why would this practice not be acceptable?

TNI Response:  If the Initial Calibration Verification (ICV) does not pass the established acceptance criteria for the calibration technique used, the calibration curve is not valid and corrective actions must be documented and samples reanalyzed. An ICV is not is not the same as a Continued Calibration Verification (CCV) and should not be evaluated against the CCV acceptance criteria.

 

Question:  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?

TNI Response:  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.  The 2003 and 2009 standards have identical language.  This section was slightly reworded in 2016 and a definition of "lot" was added to V1M2: Lot: A definite amount of material produced during a single manufacturing cycle, and intended to have uniform character and quality.  The SIR still has some relevance in further explaining this issue.

 

Question:  Does the requirement for second source standard include calibration curves for surrogate compounds?

TNI Response:  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.  The 2003 and 2009 standards have identical language.  This section was slightly reworded in 2016 and a definition of "lot" was added to V1M2: Lot: A definite amount of material produced during a single manufacturing cycle, and intended to have uniform character and quality.  The SIR still has some relevance in further explaining this issue.

 

Question:  We have been informed that Environmental lab auditors are now requiring labs to use a second vendor for their second source calibration standards even when use of a second manufactured lot from the same vendor is allowed by both the 2003 NELAC and 2009 TNI standards.   We have even heard that second source from a second manufacturer raw material prepared by the same vendor is being noted as non-compliant in some instances.  What is the interpretation of what this standard requires of labs where it applies to non-DoD programs with regard to the following options:
1. Same vendor/supplier - two independently prepared lots from the same raw material.
2. Same vendor/supplier - two independently prepared lots from different manufacturer raw materials when available.
3. Two different vendor/suppliers for each of the primary and secondary lot standards.

TNI Response:  The purpose is to verify that the standards used for calibration have been properly prepared. The verification standard must be prepared independently from the calibration standard(s). The best option is standards from two different vendors; alternatively, standards from the same vendor but different lot numbers. While the original source (manufacturer) of the neat standard is important, the standard stresses independent preparation.  The 2003 and 2009 standards have identical language.  This section was slightly reworded in 2016 and a definition of "lot" was added to V1M2: Lot: A definite amount of material produced during a single manufacturing cycle, and intended to have uniform character and quality.  The SIR still has some relevance in further explaining this issue.

 

Question:  k) The laboratory shall use and document a measure of relative error in the calibration. i, ii-a and ii-b discuss running calculations on the calibration standard results used in the curve. For metals analysis, we use ICP/ICPMS and a zero point and single calibration standard, which makes it impossible to calculate %RE or %RSE of a mid point and low level calibration standard. We are interpreting the standard to read that when a zero point, single calibration standard is used, the requirements of 1.7.1.1.k do not apply and are replaced by the requirements in the next paragraph - section 1.7.1.1.L (which specifically discuss requirements for single point calibrations.) Please confirm that we are interpreting these requirements correctly.

TNI Response:  Your interpretation is confirmed as correct.