Toxicology screen

Barbiturates - screen; Benzodiazepines - screen; Amphetamines - screen; Analgesics - screen; Antidepressants - screen; Narcotics - screen; Phenothiazines - screen; Drug abuse screen; Blood alcohol test

Toxicology screening is most often done using a blood or urine sample. However, it may be done soon after the person swallowed the medication, using stomach contents taken through gastric lavage (stomach pumping) or after vomiting.

No special preparation is needed. If you are able, tell your health care provider what drugs (including over-the-counter medications) 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.

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.

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.

Additional reasons the test may be performed:

• Alcoholism
• Alcohol withdrawal state
• Altered mental state
• Analgesic nephropathy (kidney poisoning)
• Complicated alcohol abstinence (delirium tremens)
• Delirium
• Dementia
• 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): 6 to 11 weeks with heavy use

Normal value ranges for over-the-counter or prescription medications may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

A negative value usually means that alcohol, prescription medications 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 usually reported as positive (substance is found) or negative (no substance is found).

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.

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.

Other risks associated with having blood drawn are slight but may include:

• Excessive bleeding
• Fainting or feeling light-headed
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)

Substances that may be detected on a toxicology screen include:

• Alcohol (ethanol) -- "drinking" alcohol
• Amphetamines
• Antidepressants
• Barbiturates and hypnotics
• 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