Accuracy

Laboratories will monitor accuracy and take corrective actions through the use of Standard Reference Materials (SRMs), Control Materials (CMs) or Certified Reference Materials (CRMs). 

Accuracy for an analyte in a particular SRM or CRM will be defined as having its concentration fall within the control limits (for that analyte in that particular material) that are defined as: 

Upper control limit = [1.35 * (certified concentration ±95% confidence interval)] 

and the 

Lower control limit =[ 0.65 * (certified concentration ±95% confidence interval)] 

Accuracy will be assessed during the data validation or data quality assessment stage of this investigation. See Table 3 for accuracy criteria.

Please continue with "Procedures".