How long are illegal drugs (NIDA 5 Panels) in one’s system?
When we discuss drug testing with organizations, usually the first question is “how long do illegal drugs remain in your system?” There is a different window for each type of drug. And, as important, the window depends on the size and gender of the donor. But, still people would like to know. So, here is a table from the Department of Labor that lists “estimates” of the length of time that certain drugs are detectable.
And to further complicate trying to answer the question of how long a drug is in the system, each drug has a different threshold level. Quest Diagnostics uses these threshold levels for non-DOT illegal drugs
Standard urine tests 5-panel screen for the presence of the following drugs and drug classes:
Standard 5-Panel:
| Drug Group | EIA Screen Cutoff Level* (ng/mL**) |
GC/MS Confirmation (ng/mL**) |
| Amphetamines (amphetamine and methamphetamine) |
1,000 | 500 |
| Cocaine metabolite | 300 | 150 |
| Marijuana metabolites | 50 | 15 |
| Opiates (codeine and morphine) |
2,000 | 2,000 |
| Phencyclidine | 25 | 25 |
Drugs have certain “detection windows”—the amount of time after ingestion during which evidence of their use can be detected by a drug test. Though it might not be wise to publicize detection windows and invite employees who may use drugs to push their limits, when implementing drug testing, it is important to understand them. For instance, alcohol is absorbed and eliminated more quickly than other drugs. This is why post-accident testing procedures often require testing for alcohol to occur within two hours. Other drugs are eliminated from the system at different rates and thus detectable for different periods of time, often long after the drug’s effect has worn off. The following are estimates of the length of time that certain drugs are detectable:
- Alcohol – 1 oz. for 1.5 hours
- Amphetamines – 48 hours
- Barbiturates – 2-10 days
- Benzodiazepines – 2-3 weeks
- Cocaine – 2-10 days
- Heroin Metabolite – less than 1 day
- Morphine – 2-3 days
- LSD – 8 hours
- Marijuana – casual use, 3-4 days; chronic use, several weeks
- Methamphetamine – 2-3 days
- Methadone – 2-3 days
- Phencyclidine (PCP) – 1 week
