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<br /> <br /> <br /> <br /> <br /> <br /> <br />ACZ Laboratories, Inc. August 10, 2007 <br />Quality Assurance Plan Version 12 <br />SOPAD018.08.07.12 Page 51 of 96 <br />4.66Sh <br />LLD 9' = (eXyXiXv) <br />Where : LLD95 = Lower limit of detection at the 95% confidence interval <br />Sb = Standard deviation of the instrument background counting rate, cpm <br />e, y, i, v, and u are as previously defined <br />12.4.4 Precision <br />The normalized absolute difference, or Replicate Error Ratio (RER), between the sample and the <br />laboratory duplicate, given by the following equation shall be used to determine that results do not <br />differ significantly when compared to their respective 2* sigma uncertainty. <br />RER Sx - Dupl <br />= <br />++(Dupe,,o, )Z <br />' Where: Sx = sample concentration in pCi/L <br />Sxerror = sample counting error (in pCi/L) at the 95% confidence level. <br />Dup = duplicate concentration in pCi/L <br />Duperror = duplicate counting error (in pCi/L) at the 95% confidence level. <br /> NOTE: For Radchem Drinking Water samples, both RPD and RER are used to evaluate precision. <br />i For non-Drinking Water samples, only RER is used; however, data for both RER and RPD are <br /> uploaded to LIMS for all analyses. Use the following guidelines to correctly assess precision. Further <br /> details are provided in ACZ's Wiki and must be consulted to ensure data for each workgroup is <br />' correctly evaluated. Go to LabWeb \ Wild \ Analytical Departments \ Radio Chemistry. <br /> Drinking Water: <br /> RPD < 20, RER < 2.0 - Precision is judged to be in control <br /> RPD < 20, RER > 2.0 - Precision is judged to be in control; case narrative required for RER <br /> RPD > 20, [sx] < 5x [LLD], RER < 2.0 - Precision is judged to be in control; qualify data. <br />' RPD > 20, [sx] > 5x [LLD], RER> 2.0 - Precision of the prep batch is questionable. <br /> RPD > 20, [sx] > 5x [LLD], RER < 2.0 - Precision of the prep batch is questionable. <br /> Non-Drinking Water: <br /> RER < 2.0, RPD < 20 - Precision is judged to be in control. <br /> RER < 2.0, RPD > 20 - Precision is judged to be in control; RPD must be qualified. <br /> RER > 2.0, RPD < 20 - Precision of the sample prep batch is questionable. <br /> RER > 2.0, RPD > 20 - Precision of the sample prep batch is questionable. <br /> <br />2773 Downhill Drive 970-879-6590 <br />Steamboat Springs, CO 80487 www.acz.com <br />