Application of Quality Control Results: How to Qualify Data

Wastewater Laboratory Managers, Quality Assurance Officers, and analysts are aware of the requirements to analyze quality control (QC) samples as part of each analytical batch. Method blanks, laboratory control samples, matrix spikes, matrix spike duplicates, sample duplicates, surrogates, and other QC testing are mandated by most approved methods or state/national laboratory accreditation standards. Many wastewater laboratory professionals lack a clear understanding of how to apply the QC results to the analytical data for each analytical batch, or how to qualify the batch data based on the results of the batch QC samples. Appropriate data qualifiers are critical to understanding the limitations on the use of the data for compliance purposes. Training on the proper use and application of QC data can provide wastewater professionals with the background necessary to understand the relationship between QC testing and the resultant batch data associated with it. Once this critical relationship is understood, wastewater professionals are more likely to understand the need for QC testing, are able to appropriately qualify data associated with QC failures, and are able to accurately represent the quality of the data to the end-user.