Drug Cut-off Levels

Drug Cut-off Levels when Drug Testing

Why does a drug test kit need drug cut-off levels?

When testing for drugs there needs to be a control in place to establish the point when negative becomes positive. This control or level is set by the manufacturer to recommendations by (NIDA) a department of the US government. It is important to note that a negative sample doesn’t mean that it is drug free, it might contain a drug at a concentration that is lower than the defined cut-off level.

What are Drug Cut-off levels?

This is the point at which a test is either a presumed positive or negative. A positive test is when the drug detected is above the set level for that drug. For example, if cocaine was detected, the level found will be above 300 ng/ml. Cut-off levels vary depending on which drug is tested. (see chart below)

The results from a test are displayed in panels on the face of the the device. In the image below, each panel shows two colored lines, one in the (C) area and one in the (T) area. A presumed positive is when only one colored line is visible (C) with no apparent line in the (T) area.

NOTE: Presumed positive test samples should be sent for confirmation to a SAMHSA approved lab.

Drug cut-off levels
Explanation for EliteScreen Dip Drug Test Assay.

Presumed positive for Cocaine.

From the image above, the test tells us Cocaine was detected, it indicates a ‘presumed positive‘, > 300 ng/ml was detected. Anything greater than 300 ng/ml is considered positive but to know by how much, we send the sample to a lab. They will confirm our findings and tell us how much Cocaine was found.

Should I use a laboratory if the drug cut-off levels show a presumed positive?

The short answer is YES. Whenever the screening levels are exceeded the test is presumed positive. But all drug screening tests only tell you the test is either presumed positive or negative. The urine sample when confirmed by GC/MS (Gas Chromatography/Mass Spectrometry) at a SAMHSA certified laboratory will report what drug was found and by how much. This is compared to the standard drug cut-off levels.

GC/MS confirmation is very specific when looking for drugs and also quantifies the target metabolite with a number in ng/ml. GC/MS confirmations sent to a certified laboratory will also stand up in the court of law if the test result is challenged by a donor.

Screen cut-off levels for rapid urine tests conform to the chart below as per National Institute on Drug Abuse (NIDA) recommendations.

Drug Identifier Drug cut-off Lab cut-off
Amphetamines (AMP) 1000 ng/ml 500 ng/ml
Barbiturates (BAR) 300 ng/ml 200 ng/ml
Buprenorphine (BUP) 10 ng/m 5 ng/ml
Benzodiazepines (BZO) 300 ng/ml 200 ng/ml
Cocaine 150 (COC) 150 ng/ml 150 ng/ml
Cocaine (COC) 300 ng/ml 150 ng/ml
Ecstasy (MDMA) 500 ng/m 250 ng/ml
Marijuana (THC) 50 ng/ml 15 ng/ml
Methamphetamine 500 (mAMP) 500 ng/ml 500 ng/ml
Methamphetamine (mAMP) 1000 ng/ml 500 ng/ml
Methadone (MET) 300 ng/ml 200 ng/ml
Morphine (MOP) 300 ng/ml 150 ng/ml
Opiates (OPI) 2000 ng/ml 2000 ng/ml
Oxycodone (OXY) 100 ng/m 300 ng/ml
Phencyclidine (PCP) 25 ng/ml 25 ng/ml
Propoxyphene (PPX) 300 ng/m 200 ng/ml
Tricyclic Antidepressants (TCA) 1000 ng/m 1000 ng/ml

Note: Do not compare Drug Screen cut-off levels and Lab drug cut-off levels as the testing methodology is different.

What are detection times?

Detection times are estimates and apply only to urine drug screens. There are many factors that can determine how long a particular drug can be detected in a person, these include; their age, weight, sex, metabolic rate, the amount of drug consumed and over what time frame. No conclusions can be drawn as to when a particular drug was taken or how much was consumed with urine drug screens. If you get a positive from a drug screen we recommend a lab test, which which we can arrange. More specific information can then be obtained with the results from a confirmation test. Full list of drugs and detection times for urine and oral fluid can be found here.

Category Drug Time Detectable
Opiates Heroin 1-2 days
Morphine 2 days
Methadone 3 days
Meperidine 2-3 days
Codeine 2 days
Propoxyphene 6 hours to 2 days
Oxycodone 1-3 days
Hallucinogens Lysergic Acid 1-5 days
Marijuana and Cannabinoids Single Use – 2-7 days
Prolonged Use:
30 to 45 days
Phencyclidine Single Use – 1 week
Prolonged Use:
2-4 weeks
Stimulants Cocaine Single Use – 3 days
Prolonged Use:
4 days
Amphetamines Single Use – 3 days
Prolonged Use:
7-10 days
Methylene-2, 4 dioxy-methamphetamine Single Use – 24 hours
Methamphetamine Single Use – 48 hours
Prolonged Use:
7-10 days
Barbiturates Pentobarbital 2 days
Secobarbital 2 days
Butabarbital 2 days
Butalbital 2 days
Phenobarbital 1-3 weeks
Alcohol & Metabolites Ethanol Less than 1 day
Methanol Less than 1 day
Isopropanol Less than 1 day
Acetone Less than 1 day
Ethylene Glycol Less than 1 day
Benzodiazepines Diazepam Single Use – Not detected
Prolonged Use:
5-7 days
Oxazepam Single Use – Not detected
Prolonged Use:
5-7 days
Alprazolam Single Use – Not detected
Prolonged Use:
5-7 days
Clonazepam Single Use – Not detected
Prolonged Use:
5-14 days
Chlordiazepoxide Single Use – Not detected
Prolonged Use:
5-7 days
Lorazepam Single Use – Not detected
Prolonged Use:
5-7 days
Flunitrazepam 72 hours
Gamma-Hydroxybutyrate 12 hours
Ketamine Less than 72 hours

What is a Medical Review Officer?

A medical review officer (MRO) is a physician that has been trained and certified to interpret and report drug screen results. If the lab reports a specimen as negative, the MRO signs off on the negative drug screen result. The MRO is responsible for calling a donor who has produced a positive urine specimen after the lab has reported the confirmed positive result. The MRO must ask the donor if there is any reason they can provide to justify the positive drug screen. In the case of marijuana or cocaine there is virtually no justification (except the very rare possibility of marinol, which is a prescription drug containing marijuana that can be prescribed for post chemotherapy nausea or possibly glaucoma). For positives that can result from prescription drugs, the MRO must determine if the donor has a prescription for a drug that would cause the positive drug screen result. If the donor claims to have a prescription for a drug that could have caused the positive result, then the MRO must obtain a copy of the prescription form the doctor or the pharmacy that issued the prescription. If the prescription is deemed to have caused the positive result, then the MRO reports that the drug screen was “Negative”.

Example: If the donor were to claim that they had a methamphetamine positive because they used a Vicks inhaler, then the MRO would order a d/l isomer separation to determine if the drug present in the specimen is at least 80% l-methamphetamine. If the specimen contains more than 20% d-methamphetamine, then the donor is to be considered positive for illicit methamphetamine use.

If a donor is positive for opiates and confirmed by GC/MS to contain hydrocodone and the donor’s doctor or pharmacist produces a prescription for codeine, oxycodone or some opiate drug other than hydrocodone, then the MRO must report the drug screen as positive for opiates.

An MRO also serves to redirect the donor’s specimen to a second certified laboratory in the event that the donor challenges the accuracy of the laboratory result. The MRO must then look at the drug test results form the second laboratory and determine if they are consistent with the findings from the first laboratory,

DOT drug screens require that an MRO report all drug screen results including negative results.