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method in the laboratory and is intended to be independent of instrument and analyst. Initial and on- going MDL are determined by the higher of the MDL value determined from spikes (MDLs) and the MDL value determined from method blanks (MDLb). Note that the MDL as described in this procedure is equivalent to the Limit of Detection (LOD) in the 2009 TNI Standard and is equivalent to Detection Limit (DL) in 2016 TNI Standard and may be equivalent to the DoD/DoE Quality System Manual (QSM). See chart below and Appendix 2 for comparison of terms. • Method Detection Limit Verification (MDLV) MDL verifications involve analysis of replicate spikes containing analytes at a concentration in the range of two to ten times the MDL. The MDLV is used to confirm the MDL through a) detection of a minimum response greater or equal to three (3) times the average noise; or b) a response distinguishable from the method blank. The MDLV must meet all qualitative identification criteria appropriate for the method, such as ion ratios for GC/MS or peak patterns for PCBs. Note that the LOD„ from 2009 TNI is defined as a spike 3-4x the LOD. The QSM LOD is defined as a spike 2-4x the DL (see attachment 2). Other regulatory agencies may have specific levels for a MDLv. • Limit of Quantitation (LOQ) The LOQ is the minimum quantity of a substance that can be reported with a specified degree of confidence. This is equivalent to the laboratory's routine reporting limit (RL). The LOQ must be greater than the instrument detection limit (IDL) and the MDL. Results below the LOQ are considered to be estimated values where qualitative detection is reliable, but the reliability of quantitative values is unknown. The LOQ must be greater than the MDL/DL or LOD. • Comparisons of Terms across documents: SOP term Method term 2009 TNI term 2016 TNI term QSM 5.3 term MDLs MDLs LOD(term removed DL-to be defined by in 2016) lab, minimally based on 7 replicate study MDLb MDLb MDL Initial or annual DL no current verified MDL (MDL equivalent- may be determined from used as DL if MDLs and MDLb) appropriate. MDLv Ongoing MDLs LODv (term LOD-Defined by the removed in 2016) quarterly spike LOQ ILOQ LOQ NLOQ LOQ 5) General Requirements 5.1) Frequency 5.1.1 An initial MDL study shall be performed (as described in Section 6.2): • upon method set-up, • when the laboratory has insufficient quarterly on-going MDLv data needed to perform the annual re- evaluation (see Section 6.4), or • when the method is altered in a way that can be reasonably expected to change its sensitivity. 5.1.2 On-going data are collected (as described in Section 6.3) during each quarter in which samples are being analyzed. 5.1.3 If a new instrument is added to a group of instruments whose data are being pooled to create a single MDL, analyze a minimum of 2 spiked replicates and 2 method blank replicates on the new instrument. • If both method blank results are below the existing MDL, then the existing MDLb (from Section 6.2.12) is validated. Combine the new spiked sample results to the existing spiked sample results and recalculate the MDLs, as in Section 6.2.11. • If the recalculated MDLs is in the range of 0.5 to 2.0 times the existing MDLs , then the existing MDLs, is validated. • If either of these two conditions is not met, then calculate a new MDL following the instructions in Section 6.2. 5.2) Analytes MDL studies must be performed for all target analytes that can be spiked (as discussed in Sections 2.2 and 2.3 above), with the following exceptions: • Aroclors analyzed by Method 8082 or 608.3 have many congeners in common; therefore, MDL studies