Estimate testing windows for hiring.
Detection windows depend far more on the sample type than on the substance. Blood and saliva detect only recent use, typically hours to a day or two. Urine is the standard employment matrix and extends to days. Hair testing is different in kind, giving a retrospective record of roughly 90 days. Frequency of use extends every window, because accumulated metabolites clear more slowly than a single exposure.
Window scaled by matrix and frequency
Effective window = base window x frequency multiplier x matrix factor (blood 0.25, saliva 0.4, urine 1, hair 22)
General educational information about testing science only. It is not medical, legal or employment advice, cannot predict an individual result, and must not be used to attempt to evade a lawful test. Consult a qualified professional about testing that affects you.
Because metabolites are incorporated into the growing hair shaft rather than cleared from circulation. Head hair grows about one centimetre a month, so a standard three-centimetre sample covers roughly 90 days of history.
Considerably for fat-soluble substances, where accumulation in tissue means chronic use can be detectable for weeks after occasional use would have cleared in days. For water-soluble substances the effect is much smaller.
No. They are population typicals. Metabolism, body composition, hydration, dose, purity and the specific laboratory cut-off threshold all shift the result substantially, and a screening cut-off change alone can move a window by days.