Toxicology screen
Barbiturates - screen; Benzodiazepines - screen; Amphetamines - screen; Analgesics - screen; Antidepressants - screen; Narcotics - screen; Phenothiazines - screen; Drug abuse screen; Blood alcohol testA toxicology screen refers to various tests that determine the type and approximate amount of legal and illegal drugs a person has taken by measuring how much is in their blood, urine, or other bodily fluid.
How the Test is Performed
Toxicology screening is most often done using a blood or urine sample. However, it may be done soon after the person swallowed the medicine, using stomach contents taken through gastric lavage (stomach pumping) or after vomiting.
Gastric lavage
Gastric suction is a procedure to empty the contents of your stomach.
Read Article Now Book Mark ArticleHow to Prepare for the Test
No special preparation is needed. If you are able, tell your health care provider what drugs (including prescription and over-the-counter medicines) you have taken, including when you took them and how much you consumed.
This test is sometimes part of an investigation for drug use or abuse. Special consents, handling and labeling of specimens, or other procedures may be required.
How the Test will Feel
Blood test:
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Urine test:
A urine test involves normal urination. There is no discomfort.
Why the Test is Performed
This test is often done in emergency medical situations. It can be used to evaluate possible accidental or intentional overdose or poisoning. It may help determine the cause of acute drug toxicity, monitor drug dependency, and determine the presence of substances in the body for medical or legal purposes.
Acute
Acute means sudden. Acute symptoms appear, change, or worsen rapidly. It is the opposite of chronic.
Read Article Now Book Mark ArticleAdditional reasons the test may be performed include:
- Alcohol use disorder
Alcohol use disorder
Alcohol use disorder is when your drinking causes serious problems in your life, yet you keep drinking. You may also need more and more alcohol to f...
Read Article Now Book Mark Article - Alcohol withdrawal state
Alcohol withdrawal state
Alcohol withdrawal refers to symptoms that may occur when a person who has been drinking too much alcohol on a regular basis suddenly stops drinking ...
Read Article Now Book Mark Article - Altered mental state
- Analgesic nephropathy (kidney poisoning)
Analgesic nephropathy
Analgesic nephropathy involves damage to one or both kidneys caused by overexposure to mixtures of medicines, especially over-the-counter pain medici...
Read Article Now Book Mark Article - Complicated alcohol abstinence syndrome (delirium tremens)
Complicated alcohol abstinence syndrome...
Delirium tremens is a severe form of alcohol withdrawal. It involves sudden and severe mental or nervous system changes.
Read Article Now Book Mark Article - Delirium
Delirium
Delirium is sudden severe confusion due to rapid changes in brain function that can occur with physical or mental illness.
Read Article Now Book Mark Article - Dementia
Dementia
Dementia is a loss of brain function that occurs with certain diseases. It affects one or more brain functions such as memory, thinking, language, j...
Read Article Now Book Mark Article - Drug abuse monitoring
- Fetal alcohol syndrome
- Intentional overdose
- Seizures
- Stroke caused by cocaine use
- Suspected sexual assault
- Unconsciousness
If the test is used as a drug screen, it must be done within a certain amount of time after the drug was taken, or while forms of the drug can still be detected in the body. Examples are below:
- Alcohol: 3 to 10 hours
- Amphetamines: 24 to 48 hours
- Barbiturates: up to 6 weeks
- Benzodiazepines: up to 6 weeks with high level use
- Cocaine: 2 to 4 days; up to 10 to 22 days with heavy use
- Codeine: 1 to 2 days
- Heroin: 1 to 2 days
- Hydromorphone: 1 to 2 days
- Methadone: 2 to 3 days
- Morphine: 1 to 2 days
- Phencyclidine (PCP): 1 to 8 days
- Propoxyphene: 6 to 48 hours
- Tetrahydrocannabinol (THC): up to 6 to 11 weeks with heavy use
Normal Results
Normal value ranges for over-the-counter or prescription medicines may vary slightly among different laboratories. Talk to your provider about the meaning of your specific test results.
A negative value most often means that alcohol, prescription medicines that have not been prescribed, and illegal drugs have not been detected.
A blood toxicology screen can determine the presence and level (amount) of a drug in your body.
Urine sample results are often reported as positive (substance is found) or negative (no substance is found).
What Abnormal Results Mean
Elevated levels of alcohol or prescription drugs can be a sign of intentional or accidental intoxication or overdose.
The presence of illegal drugs or drugs not prescribed for the person indicates illicit drug use.
Illicit drug use
Substance use is the continued use of alcohol, illegal drugs, or the misuse of prescription or over-the-counter medicines with negative consequences....
Read Article Now Book Mark ArticleSome legal prescription and over-the-counter medicines may interact with the testing chemicals and false results in urine tests. Your provider will be aware of this possibility.
Risks
Risks associated with having blood drawn are slight but may include:
- Excessive bleeding
- Fainting or feeling lightheaded
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
Considerations
Substances that may be detected on a toxicology screen include:
- Alcohol (ethanol) -- "drinking" alcohol
- Amphetamines
- Antidepressants
- Barbiturates and hypnotics
Hypnotics
Some people may need medicines to help with sleep for a short period of time. But in the long run, making changes in your lifestyle and sleep habits...
Read Article Now Book Mark Article - Benzodiazepines
- Cocaine
- Flunitrazepam (Rohypnol)
- Gamma hydroxybutyrate (GHB)
- Marijuana
- Narcotics
- Non-narcotic pain medicines, including acetaminophen and anti-inflammatory drugs
- Phencyclidine (PCP)
- Phenothiazines (antipsychotic or tranquilizing medicines)
- Prescription medicines, any type
References
Bluth MH, Pincus MR, Abraham NZ. Toxicology and therapeutic drug monitoring. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 24.
Langman LJ, Bechtel LK, Holstege CP. Clinical toxicology. In: Rifai N, Chiu RWK, Young I, Burnham Carey-Ann D, Wittwer CT, eds . Tietz Textbook of Laboratory Medicine. 7th ed. St Louis, MO: Elsevier; 2023:chap 43.
Minns AB, Clark RF. Substance abuse. In: Walls RM, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 187.
Mofenson HC, Caraccio TR, McGuigan M, Greensher J. Medical toxicology. In: Kellerman RD, Rakel DP, Heidelbaugh JJ, Lee EM, eds. Conn's Current Therapy 2023. Philadelphia, PA: Elsevier; 2023:1404-1457.
Blood test - illustration
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.
Blood test
illustration
Blood test - illustration
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.
Blood test
illustration
Review Date: 1/2/2023
Reviewed By: Jesse Borke, MD, CPE, FAAEM, FACEP, Attending Physician at Kaiser Permanente, Orange County, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.