Accuracy is the correlation between the PCR results and “known” positive reference results. These may be commercially obtained (with certificates of analysis) or specimens obtained from reference laboratories or colleagues who run the same assays. It is important to test varying levels of the targets.
Precision of an analytical procedure is the correlation in agreement between a series of measurements obtained from multiple sampling of the homogeneous sample performed under the exact assay conditions. There are three levels of precision, including:
- Repeatability: Expresses the precision under the same operating conditions over a short interval of time. Repeatability is also termed intra-assay precision.
- Intermediate precision: Expresses within-laboratories variations (eg, different days, different analysts, different equipment, etc.).
- Reproducibility: Expresses the precision between laboratories (collaborative studies usually applied to standardization of methodology).