Cutoff
The term cutoff (also cut-off) or tolerance limit describes a tolerance value in the analysis of drugs and medication . It defines from when a test result is to be assessed as positive or negative. The cutoff must be distinguished from the detection limit .
Sense and purpose
Due to the sensitivity and accuracy of today's measurement methods, a limit value is set in the analysis of narcotics and drugs, which is precisely chosen so that accidental contamination such as passive smoking and thus "false positive" results are avoided. If one were to exploit the full sensitivity, for example, mere passive smoking of a cannabis cigarette or touching a bank note contaminated with drugs would lead to a positive result and could possibly also burden abstinent people.
It is therefore quite possible that a test result is rated as negative, although drugs or medication could be found, provided that one is below the cutoff. In the case of actual consumption, the detected amount of the substance corresponds approximately to ten to a thousand times the amount of the cutoff value.
Magnitude
The cutoff is only qualitatively defined internationally; quantitatively, it can differ in every laboratory. There are recommended limits from the National Institute on Drug Abuse (NIDA). For most substances, they are usually between 50 and 1000 ng / ml sample.
In the road traffic regulations, a positive drug test is generally classified as an administrative offense , which is why the cutoff is usually significantly lower. The amount of substance that can be influenced by the substance is relevant here. For example, a value of 1 ng / ml sample applies to cannabis, while most drug screenings provide a limit value of approx. 50 ng / ml sample.
In order to guarantee the reliability of the detection and thus avoid false positive results, the cutoff is several times above the detection limit .
See also
Web links
Individual evidence
- ↑ Ecomed Medicine: Analysis of Drugs and Medicines in Urine
- ↑ University Hospital Tübingen: Drug screening in urine
- ↑ Ecomed Medicine: Analysis of Drugs and Medicines in Urine
- ↑ Drug Knowledge: Cut-Off
- ↑ University Hospital Tübingen: Drug screening in urine