What Does “Sensitivity” and “Cutoff” Mean in Drug Testing?
The ability of any test to detect low level of drugs has an inherent limit. The concentration of a drug in the urine sample, below which a test can no longer be considered reliable, is the “sensitivity” limit. The “cutoff” point is the concentration limit that will actually be used to test the samples. Any sample testing below this level is considered a negative. Manufacturers of commercial urine screening systems set cutoff limits of their tests well above the sensitivity limits to assure accuracy and reliability and to minimize the possibility of a sample which is truly negative giving a (false) positive result.
