Random screening – Effective drug testing must be random. This means it should be unexpected, unannounced, and unanticipated. Testing should be conducted as often as possible, preferably at least twice a week. Some times testing should be done on back-to-back days, to let participants know that they are not “in the clear” for a few days after being tested
Drugs tested – Typically, drug screens do not test for all drugs. The basic drug test used by most corporate drug testing programs is called a Five-Screen (or NIDA-5 or SAMHSA-5) which is testing for five types of drugs:
- Cannabinoids (Marijuana, Hashish)
- Cocaine (Cocaine, Crack, Benzoylecognine)
- Opiates (Heroin, Opium, Codeine, Morphine)
- Amphetamines (Amphetamines, Methamphetamines, Speed)
- Phencyclidine (PCP, Angel Dust)
Many drug testing firms also offer a ten-screen, which is based on the five above drugs, but adds an additional five for testing:
- Barbituates (Phenobarbital, Secobarbitol, Pentobarbital, Butalbital, Amobarbital)
- Methaqualone (Qualuudes)
- Benzodiazepines (Tranquilizers-Diazepam, Valium, Librium, Ativan, Xanax, Clonopin, Serax, Halcion, Rohypnol)
- Propoxyphene (Darvon compounds)
Creatinine - Creatinine is a substance found in urine. One of the most common strategies to “beat” a drug test involves ingesting excessive amounts of water, or taking diuretics to “flush” out the system. This produces abnormally low levels of creatinine. Normal urine creatinine levels for random urine collections are typically observed between 40-250 mg/dL, with a mean around 100 mg/dL. Samples with creatinine levels below 20 mg/dL are not acceptable and are reported as diluted, invalid, or substitued depending on the creatinine levels when compared to the urine density (specific gravity). It should be noted that diluted samples may not be due to a conscious effort of subversion, and cannot be proved to be intentional. The absence of creatinine (<5mg/dL) is indicative of a specimen not consistent with human urine.
Interpretation of Positive Results - Indicates that a drug, or its metabolites were tested for and detected in the sample. The amount exceeds the cut off level, and may need to be confirmed with a follow-up test. The gold-standard confirmation test is gas chromatography-mass spectrometry (GC/MS).
Are detailed results needed? - According to Paul Cary, Director of the Toxicology Laboratory at the University of Missouri, detailed information is not needed. Screening and monitoring tests are designed to determine the absence or presence of a drug, not the concentration. There are too many factors which might influence the concentration of a substance in a given sample.
Screening and marijuana (Cannabinoids) – the cutoff levels are 50 ng/mL. It may be difficult to separate out recent from longer term use, since THC is stored in lipids. Passive inhalation (second hand smoke) should not result in a positive screen, because the levels will be below the 50 ng/mL cutoff. Detection time for infrequent users is thought to be 1 – 3 days; for chronic users usually by 3 weeks, although some outliers may take longer to eliminate the THC below the cutoff levels.
Screening and amphetamines – positive results should be interpreted with caution, because some screening tests have cross-reactivity with other substances, such as ephedrine. Results should be confirmed whenever possible. Detection time is up to 4 days after use.
Screening and cocaine – positive results are almost always associated with illicit drug use. However, a negative result may not be a clear indication of non-use. Detection time is up to a maximum of 3 days.
Screening and opiates – most screenings do not detect synthetic narcotic analgesics, such as Demerol, Darvon, methadone, Talwin, and fentanyl. It can be difficult to separate out legitimate use from abuse. Detection time is up to 4 days after use.
Screening and alcohol – this can be accomplished throuhg urine, saliva, blood, or breath testing. Alcohol is rapidly clearly from the body and detection timeframes are just a few hours. This means that negative results don’t necessarily document abstinence. One option, although more expensive that regular alcohol testing is screening for Ethyl Glucuronide (EtG), which is detecable for 2 – 5 days. This screening tool is only available from select laboratories.
Click here for an easy to use chart on detection times.