Drugs of Abuse Testing
Tools and References
View information about specific drug categories.
Tests to monitor serum levels of drugs to determine if a patient is receiving the optimum dose.
Print/download PDFs and tables of information.
Used if test results could be challenged in a court of law.
Low-cost screening to identify drugs of abuse by class.
Test to manage an overdose, intoxicated patient, or determine if symptoms are due to the presence of drugs.
A more thorough test to confirm abuse.
Detecting attempts to "beat the test."
Tests to confirm the type of drug.
Specific Drug Groups Interpretive Guide
Use the following links to view information for specific drug categories:
- Approximate Detection Times Table for all specific drug groups
- Limits-of-Detection Table for prescription and over-the-counter drugs
Drug Abuse Survey
- This test is intended to be used by a physician or trained drug abuse counselor and interpreted in the context of the patient's symptoms and clinical and medication history.
- This is a screening immunoassay to identify drugs of abuse by class.
Note: This test is performed on urine specimens only.
- This test has a high negative predictive value.
- Cross-reactivity: this test has a false-positive rate of approximately 5%.
Note: The false-positive rate varies by analyte.
- Positive results are not definitive, and should be considered presumptive.
- This test is not intended to be used for employee drug screening.
The advantage of this test is low cost. The cross-reactivity of the antibody used in the assay varies by drug. For example, the test for amphetamines detects amphetamine with greatest sensitivity, but it cross-reacts with over-the-counter (OTC) sympathomimetics, such as pseudophedrine, if they are present in urine at high concentrations.
Confirmed Drug Abuse Survey
- This test is designed for clinical circumstances where the patient may be inclined to deny the test results.
- The test uses the same immunoassay as the Drug Abuse Survey to screen samples but also includes confirmation of screening results by more definitive analytical techniques.
Note: This test is designed to provide definitive test results.
- All positive screen results are confirmed by gas chromatography with flame ionization detection (GC-FID), gas chromatography/mass spectrometry (GC/MS), or liquid chromatography/tandem mass spectrometry (LC/MS/MS).
- This test can be ordered in a variety of configurations, differing only by the target drugs.
When results must be definitive, the Confirmed Drug Abuse Survey provides a fast and cost-effective approach to screening for drugs of abuse. It takes advantage of the negative predictive value of the immunoassay screen and couples it with the true-positive capability of the confirmation techniques. When a drug is present, the report identifies the specific drug and concentration.
Specific Drug Group Confirmation
- These tests are designed to evaluate a patient known to use a specific drug.
- Tests are available for each drug of abuse class.
- This test is designed to detect lower concentrations of a drug.
- This test is useful when a drug may have a low cross-reactivity in the screening assay (eg, oxycodone in the urine opiate assay).
Note: More sensitive and specific than screening tests.
- All drugs tested are named in the report.
- Concentration is reported down to the limit of quantitation (LOQ) of the assay.
- Available confirmation tests include:
- Amphetamine Confirmation, Urine
- Barbiturate Confirmation, Urine
- Benzodiazepine Confirmation, Urine
- Cocaine Confirmation, Urine
- Fentanyl Confirmation, Urine
- Ketamine Confirmation, Urine
- Lysergic Acid Diethylamide (LSD) Confirmation, Urine
Opiates Confirmation, Urine
- Methadone Confirmation, Urine
- Phencyclidine (PCP) Confirmation, Urine
- Tetrahydrocannabinol (THC) Confirmation, Urine
- Fentanyl, Serum
Morphine Confirmation, Serum
Oxycodone, Unconjugated, Serum
Therapeutic Drug Monitoring
These tests monitor serum levels of drugs to determine if a patient is receiving the optimum dose are also available from Mayo Medical Laboratories.
Mayo Medical Laboratories does not perform workplace drug testing. In other circumstances where the test results could be challenged in a court of law, a chain of custody process should be utilized.
- Chain of custody starts at the time of initial patient contact. The specimen must be collected under controlled conditions. The collection facility initiates a documentation process that accompanies the specimen to the laboratory. The chain-of-custody process provides:
- Clear and unique identification of the subject being tested
- Clear and unique labeling of the specimen
- Identification of all persons who handle the specimen—legible signature required
- A historical record of events with action dates clearly stated
- Security of the specimen using a sealed, tamper-evident process
Failure to complete the collection process correctly, including labeling of the sample, as well as all details of the accompanying documentation, may result in the inability to process the sample.
A convenient kit is available to facilitate the chain-of-custody process.
Prescription and Over-the-Counter (OTC) Drug Screens
- This test is intended to manage an apparent overdose, intoxicated patient, or determine if a specific set of symptoms might be due to the presence of drugs.
- This test is designed to detect those drugs that have toxic effects, but drugs for which there are known antidotes or active therapies to treat the toxic effect.
- This test is not appropriate for detecting drugs of abuse. The test is not designed to screen for intermittent or illicit use of drugs.
The prescription and OTC drug screens are available to test for a broad spectrum of drugs in serum and urine. Testing is performed by GC/MS. When drugs are identified above the reportable (detection) limits in the specimen, they will be reported as "Present."
Note: Alcohol, LSD, digoxin, lithium, tetrahydrocannabinol (THC), and some benzodiazepines, opiates, amphetamine-type stimulants, and most drugs of abuse are not detected by this procedure. For these drugs, the specific confirmation tests should be ordered.
Limits of Detection (LOD)
May only be able to detect drug when taken in excess, therapeutic administration may not be detected.
Attempts to "beat the test" usually involve the use of a masking agent. Masking agents function as either an assay-interfering substance or a urine diluent.
Adulterant testing is performed for urine drugs of abuse tests.