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Emergency Toxicology. ARUP Consult®. Retrieved September 28, 2023, https://arupconsult.com/content/emergency-toxicology

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Emergency Toxicology

Emergency toxicology focuses on the diagnosis, management, and prevention of poisoning due to drugs, occupational and environmental toxins, and biological agents. Examples of exposures include acute drug overdoses, hazardous exposure to chemical products, and the management of drug withdrawal syndromes.  

Quick Answers for Clinicians

When should specimens be collected for emergency toxicology testing?

In emergency situations, there are no specific timing recommendations; instead, specimens should be collected as soon as possible.

Which specimens are appropriate for emergency toxicology testing?

Whole blood, serum, or plasma specimens are typically preferred for most testing; quantitative results can be used to assess signs and symptoms of toxicity. Urine can be used to assess acute or chronic exposure within an average window of detection of 1-3 days.

How should toxicology test results be interpreted?

Test results should be interpreted based on the established therapeutic or toxic range (if applicable), timing of specimen collection relative to the time of exposure, specimen type, and the patient’s clinical signs and symptoms of toxicity. Concomitant medications and factors relevant to the window of detection will also affect the interpretation of results (see Frequently Asked Questions). Note that adverse drug responses can occur even when drug concentrations are within the therapeutic range.

Toxicology test results are useful not only to determine patient exposure and assess symptoms of toxicity, but also for serial monitoring to evaluate treatment efficacy and determine if toxin concentrations have decreased over time.

Indications for Testing

Testing for toxicity may be indicated in the following situations:

  • Accidental or intentional poisoning from illicit or licit substances
  • Decontamination or detoxification
  • Suspected overdose of licit or illicit substances in a patient presenting with altered cognition
  • Metabolic acidosis of unknown cause
  • Signs and symptoms of toxicity in the event of a known or suspected hazardous exposure

Timing of Specimen Collection

In an acute emergency, specimens should be collected as soon as possible if toxicity is suspected. If assessing decontamination or detoxification (eg, in the case of acetaminophen poisoning), retest intervals are determined on a case-by-case basis.

Specimen Selection

Whole blood, serum, or plasma is preferred for most testing because these specimens can provide both quantitative and qualitative information. Urine may be used in select cases when only qualitative information is needed.

Frequently Asked Questions

What is the definition of half-life?

The half-life of a drug refers to the time required for 50% of the drug to be eliminated from blood.

What is the definition of steady-state concentration?

Steady-state concentration occurs when the rate of drug administration is equal to the rate of elimination. Generally, steady-state concentration can be achieved after an individual has consistently administered the drug for the duration of 5-7 half-lives (eg, if a drug has a half-life of 24 hours and is administered once a day, then steady-state concentration can be achieved after 5-7 days of drug administration).

What is the window of detection of drugs in blood, serum, plasma, and urine specimens?

In general, the window of detection in blood, serum, and plasma is 1-2 days after drug administration. Urine specimens typically have an average window of detection of 1-3 days.

The window of detection for drugs is dependent on several factors, including the following:

  • Half-life of the drug
  • Drug dose
  • Frequency of drug administration
  • Route of administration
  • Drug formulation
  • Chemistry of the drug (eg, solubility, stability)
  • Patient age
  • Patient body composition and sex
  • Patient pathophysiology and pharmacokinetics
  • Coadministration of other medications
  • Hydration and nutrition status
  • Analytical limitations of testing

Can gel separator tubes be used for toxicology testing?

Gel separator tubes are not recommended for testing in toxicology. Drugs that are lipid soluble may be absorbed into the gel, which may cause a falsely low result.

Further Resources

ARUP Laboratory Tests

Alcohol Tests

Note: Refer to ARUP Consult’s Alcohol Use Biomarkers topic for more testing options.

Toxic level: >100 mg/dL

Toxic level:

  • Isopropanol: >50 mg/dL
  • Acetone, quantitative: >100 mg/dL
  • Ethanol: >250 mg/dL
  • Methanol: >20 mg/dL

Toxic level: >250 mg/dL

Toxic level: >20 mg/dL

Toxic level:

  • Isopropanol: >50 mg/dL
  • Acetone, quantitative: >100 mg/dL

Toxic level: >20 mg/dL

Anticonvulsant/Antiepileptic Tests

Note: Refer to ARUP Consult’s Therapeutic Drug Monitoring topic for testing options.

Antidepressant Tests

Note: Refer to ARUP Consult’s Therapeutic Drug Monitoring topic for testing options.

Antipsychotic Tests

Note: Refer to ARUP Consult’s Therapeutic Drug Monitoring topic for testing options.

Cannabinoid Tests

Drug Detection Tests

For a complete list of drugs and drug metabolites detected, refer to the Drug Profile, Expanded Targeted Panels Test Fact Sheet 

For a complete list of drugs and drug metabolites detected, refer to the Drug Profile, Expanded Targeted Panels Test Fact Sheet 

Drug-Facilitated Sexual Assault Tests

Illicit Drug Tests

Nonopioid Pain Medication Tests

Note: Also refer to ARUP Consult’s Drug Testing topic for testing options.

Critical toxic values:

  • 4 hrs after ingestion: >150 µg/mL
  • 12 hrs after ingestion: >40 µg/mL

Toxic level: ≥31 mg/dL

Opiate/Opioid Analgesic Tests

Note: Refer to ARUP Consult’s Therapeutic Drug Monitoring and Drug Testing topics for more testing options.

Other Toxicant Tests

Sedative-Hypnotics Tests

Note: Refer to ARUP Consult’s Therapeutic Drug Monitoring topic for testing options.

Stimulant Tests

Note: Refer to ARUP Consult’s Nicotine Exposure and Metabolites topic for more testing options.

Trace and Toxic Element Tests

Note: Refer to ARUP Consult’s Trace Elements–Deficiency and Toxicity topic for testing options. 

References

Additional Resources

Related Information From ARUP Laboratories

Topics From ARUP Consult

Alcohol Use Biomarkers
Drug Testing
Germline Pharmacogenetics - PGx
Newborn Drug Screening - Meconium and Umbilical Cord Tissue
Nicotine Exposure and Metabolites
Therapeutic Drug Monitoring - TDM
Trace Elements - Deficiency and Toxicity

Selected Scholarly Publications From ARUP Laboratories

Educational Videos From ARUP Laboratories

Laboratory Testing for Biomarkers of Alcohol Exposure
66 min

Medical Experts

Contributor
Contributor

McMillin

Gwendolyn A. McMillin, PhD
Gwendolyn A. McMillin, PhD
Professor of Pathology (Clinical), University of Utah
Scientific Director, Mass Spectrometry Platform; Medical Director, Clinical Toxicology and Pharmacogenomics, ARUP Laboratories