If no permitted limit has been established for a substance, the decision limit is the lowest concentration level at which a method can discriminate with a statistical certainty of 1 - α that the particular analyte is present.
Kui aine puhul piirnormi kehtestatud ei ole, on otsustamispiiriks madalaim kontsentratsioon, mille juures saab statistilise kindlusega 1 α kinnitada, et konkreetne analüüt on olemas.