Quality system standards for testing laboratories (ASTM D6792 and ISO 17025) require the use of processes to manage precision and bias. Several ASTM International standards guide users in the quality assurance and quality control (QA/QC) practices for managing precision and bias within a testing laboratory (e.g., D6299, D6617, E882 and E1323). Some deal specifically with laboratories servicing the petroleum products and lubricants industry. Many of these practices focus on within-laboratory precision (repeatability). Using certified reference standards and statistical quality control (SQC) techniques like control charts are two widely used tools employed to satisfy requirements to manage precision and bias within a laboratory.