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Emergency Toxicology. ARUP Consult®. Retrieved August 07, 2020, 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 Lab Tests

Alcohol Tests

Note: Refer to ARUP Consult’s Alcohol Use Biomarkers and Metabolic Acidosis topics for more testing options.

Use to monitor exposure to acetone

Toxic level: >100 mg/dL

Use to identify ethanol, methanol, isopropanol, or acetone ingestion

Toxic level:

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

Use to identify acute alcohol ingestion

Toxic level: >250 mg/dL

Useful for general screening to assess ethanol exposure in the context of compliance and/or abuse

Aids in assessment of the etiology of anion gap acidosis

Use to detect ethylene glycol poisoning

Toxic level: >20 mg/dL

Use to monitor exposure to isopropanol

Toxic level:

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

Use to monitor exposure to methanol

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

Use to detect exposure to cannabinoids

May be useful in the assessment of exposure to synthetic cannabinoids up to several days after exposure

Drug Detection Tests

May be useful to assess acute exposure to bath salts

For assessment several days after exposure, refer to Bath Salts Panel, Urine (2008650)

May be useful to assess exposure to bath salts up to several days after exposure

To assess acute exposure, Bath Salts Panel, Serum or Plasma (2011411) may be useful

Use to detect overdose exposure

Useful when identity or class of the drug or drugs of interest is not known

Not recommended for assessment in routine compliance and/or abuse contexts

Use to monitor patient compliance

Drug-Facilitated Sexual Assault Tests

Use to detect exposure

Useful for general screening for drug abuse

Positive drug screen results are confirmed

Use to monitor patient adherence and exposure

Illicit Drug Tests

Use to detect exposure

Useful for general screening for drug abuse

Positive drug screen results are confirmed

Use to monitor patient adherence

Nonopioid Pain Medication Tests

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

Aids in the assessment of acetaminophen toxicity

Critical toxic values:

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

Use to optimize drug therapy and monitor patient adherence

Aids in assessment of the etiology of anion gap acidosis

Refer to ARUP Consult topic Metabolic Acidosis for more information

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.

Useful for general screening in context of compliance and/or abuse

For follow-up testing of a presumptive result, Buprenorphine and Metabolites, Urine, Quantitative (2010092) is preferred

Useful for general screening in context of compliance and/or abuse

For follow-up testing of a presumptive result, Fentanyl and Metabolite, Urine Quantitative (0092570) is preferred

Useful for general screening in context of compliance and/or abuse

For follow-up testing of a presumptive result, Meperidine and Metabolite, Urine, Quantitative (3000248) is preferred

Preferred test to follow up presumptive results

For general screening, Opiates, Urine Screen with Reflex to Quantitation (2005093) is preferred

Use to monitor patient adherence

For follow-up testing of a presumptive result, Opiates, Urine, Quantitative (0090364) is preferred

Useful for general screening in context of compliance and/or abuse

For follow-up testing of a presumptive result, Tapentadol and Metabolite, Urine, Quantitative (2003128) is preferred

Useful for general screening in context of compliance and/or abuse

For follow-up testing of a presumptive result, Tramadol and Metabolites, Urine, Quantitative (2002736) is preferred

Other Toxicant Tests

Use to monitor cyanide exposure

Toxic level: >100 µg/dL

Use to diagnose increased carbon monoxide (CO) levels and CO poisoning

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.

Use to detect exposure

Use to monitor patient adherence

Use to detect and monitor concentrations of nicotine, cotinine, and trans-3’-hydroxycotinine in serum or plasma

Serum or plasma testing may be useful when a valid urine specimen cannot be obtained (eg, patient is anuretic or undergoing dialysis)

Trace and Toxic Element Tests

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

Medical Experts

Contributor
Contributor

McMillin

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

References

Additional Resources
Resources from the ARUP Institute for Clinical and Experimental Pathology®

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