EDL, MDL And LOQ: Understanding Detection Limits In Water Analysis

Accurate water-quality reporting relies on understanding the distinct roles of estimated detection limits (EDL), method detection limits (MDL), and limits of quantification (LOQ). While the EDL indicates what a method can theoretically detect under ideal conditions, it does not account for real-world laboratory variables like specific instrumentation, reagents, or operator technique. The MDL establishes the lowest analyte concentration a specific facility can distinguish from zero with 99% confidence, providing experimentally verified proof of detection capabilities. Moving beyond simple detection, the LOQ defines the threshold where concentrations can be quantified with defined precision and accuracy. Differentiating these metrics ensures laboratories select appropriate analytical methods, prevent overstating data certainty, and report defensible compliance results. Read the complete guide to optimize your laboratory's reporting practices.