Method Detection Limit - Definition.

Modified on: Fri, 12 Nov, 2021 at 11:30 AM

Method Detection Limit or "MDL".

It is the smallest analyte concentration that can be demonstrated to be different from zero or a blank concentration at the 99% level of confidence. In other words, if a substance is detected at or above the DL, it can be reliably stated (with 99% confidence) that the analyte is present (there is a 1% chance that the analyte is not present (a false positive)). Note that for reporting purposes, any result at or above the DL must also meet qualitative identification criteria required by the test method. 

Note: The Limit of Detection (LOD) is the smallest amount or concentration of a substance that must be present in a sample in order to be detected at a 99% confidence level. In other words, if a sample has a true concentration at the LOD, there is a minimum probability of 99% of reporting a “detection” (a measured value ≥ DL) and a 1% chance of reporting a non-detect (a false negative). The failure to obtain a “detection” should be reported as “<LOD", because the false negative rate at the LOD is1%.  Reporting the samples result as "<DL" is inappropriate because, as stated above, the false negative rate at the DL is 50%.

Go here for Reporting Detection Limit.

For information on specific test or parameter detection limits, please contact our Customer Solutions team in one of the following ways:  

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    • Phone: 1.833.BVC.LABS (833.282.5227)

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