Calculating and Using Method Detection Limits

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EPA defines method detection limit (MDL) as the minimum measured concentration of a substance that can be reported with 99% confidence that the measured concentration is distinguishable from method blank results. The Code of Federal Regulations (40 CFR Part 136) requires laboratories to include MDLs in their regulatory test procedures when measuring water and wastewater analytes. MDLs are important reference points that enable labs to measure the analyte at the proper sensitivity through the appropriate instruments and methods. They also ensure agencies can make regulatory decisions based on known scientific constraints. In 2016, the MDL procedure was updated by EPA. Join this webcast for an interactive primer on how MDLs are used by labs and regulatory agencies and the current way to calculate them.

The Calculating & Using Method Detection Limits webinar will define the importance of MDLs for use within a laboratory and in making regulatory decisions. It will include an interactive component in which participants will calculate a detection limit utilizing a calculation spreadsheet and provided data.


  • Elizabeth Turner, Pace Analytical Services
  • Jack Bennett, Lawrence Livermore National Laboratory
  • Mary Johnson, Rock River Water Reclamation District
  • Dale Baker (moderator), Garrett County Public Utilities

There will be 2.0 Professional Development Hours (PDHs) offered for this webcast. Please check with your state accreditation agency to determine if you qualify.