Method Detection Limit (MDL)
"Method detection limit," or "MDL," means 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 MDL is generated according to the procedure specified in the latest revision of 40 CFR Part 136, Appendix B.
"Limit of detection" or "LOD" means the lowest concentration or amount of analyte that can be identified, measured and reported with confidence that the concentration is not a false positive value. The department considers the LOD to be equivalent to the method detection limit.
- DNR MDL Spreadsheet - basic version [XLS]
- DNR MDL Spreadsheet - advanced version (includes information for chromatography) [XLS]
- DNR MDL Spreadsheet - advanced multi-parameter version [XLS]
- DNR MDL Spreadsheet instructions [DOCX]
- DNR MDL Procedure instructions [DOCX]
- DNR WWOA 2018 Presentation on MDL Changes
- EPA MDL Procedure Revision 2
- EPA 2018 Presentation on the New MDL Procedure
- EPA MDL FAQ
- TNI 2017 Presentation on the New MDL Procedure
If you have any questions on MDLs, please do not hesitate to reach out to a Laboratory Accreditation Program Auditor.