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
In emergency situations, there are no specific timing recommendations; instead, specimens should be collected as soon as possible.
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.
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
Use to monitor exposure to acetone
Quantitative Gas Chromatography
Toxic level: >100 mg/dL
Use to identify ethanol, methanol, isopropanol, or acetone ingestion
Quantitative Gas Chromatography
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
Quantitative Gas Chromatography
Toxic level: >250 mg/dL
Useful for general screening to assess ethanol exposure in the context of compliance and/or abuse
Qualitative Enzyme Immunoassay/Quantitative Liquid Chromatography-Tandem Mass Spectrometry
Aids in assessment of the etiology of anion gap acidosis
Use to detect ethylene glycol poisoning
Quantitative Enzymatic Assay
Toxic level: >20 mg/dL
Use to monitor exposure to isopropanol
Quantitative Gas Chromatography
Toxic level:
- Isopropanol: >50 mg/dL
- Acetone, quantitative: >100 mg/dL
Use to monitor exposure to methanol
Quantitative Gas Chromatography
Toxic level: >20 mg/dL
Note: Refer to ARUP Consult’s Therapeutic Drug Monitoring topic for testing options.
Note: Refer to ARUP Consult’s Therapeutic Drug Monitoring topic for testing options.
Note: Refer to ARUP Consult’s Therapeutic Drug Monitoring topic for testing options.
Use to detect exposure to cannabinoids
Quantitative Liquid Chromatography-Tandem Mass Spectrometry
May be useful in the assessment of exposure to synthetic cannabinoids up to several days after exposure
Qualitative High Performance Liquid Chromatography-Tandem Mass Spectrometry
May be useful to assess acute exposure to bath salts
Qualitative High Performance Liquid Chromatography-Tandem Mass Spectrometry
May be useful to assess exposure to bath salts up to several days after exposure
Qualitative High Performance Liquid Chromatography-Tandem Mass Spectrometry
Use to detect drug exposure from among a targeted list of prescriptions, over-the-counter medications, and illicit drugs Not recommended to determine medication compliance or to assess for undisclosed drug/substance use in the context of pain management, substance use disorder treatment, or any other pharmacotherapies involving controlled substances
Qualitative Liquid Chromatography-Tandem Mass Spectrometry
For a complete list of drugs and drug metabolites detected, refer to the Drug Profile, Expanded Targeted Panels Test Fact Sheet
Qualitative Liquid Chromatography-Tandem Mass Spectrometry
For a complete list of drugs and drug metabolites detected, refer to the Drug Profile, Expanded Targeted Panels Test Fact Sheet
Use to monitor patient compliance
Qualitative Enzyme-Linked Immunosorbent Assay (ELISA)/Quantitative Gas Chromatography-Mass Spectrometry (GC-MS)/Quantitative Liquid Chromatography-Tandem Mass Spectrometry
Use to detect exposure
Qualitative High Performance Liquid Chromatography-Tandem Mass Spectrometry
Qualitative High Performance Liquid Chromatography-Tandem Mass Spectrometry
Useful for general screening for drug abuse
Positive drug screen results are confirmed
Gas Chromatography-Mass Spectrometry
Qualitative Gas Chromatography-Mass Spectrometry/Quantitative Gas Chromatography-Mass Spectrometry
Use to monitor patient adherence and exposure
Quantitative Gas Chromatography-Mass Spectrometry
Use to detect exposure
Quantitative Gas Chromatography-Mass Spectrometry/Quantitative Liquid Chromatography-Tandem Mass Spectrometry
Quantitative High Performance Liquid Chromatography-Tandem Mass Spectrometry
Useful for general screening for drug abuse
Positive drug screen results are confirmed
Qualitative Enzyme-Linked Immunosorbent Assay/Quantitative High Performance Liquid Chromatography-Tandem Mass Spectrometry
Use to monitor patient adherence
Quantitative Gas Chromatography-Mass Spectrometry
Note: Also refer to ARUP Consult’s Drug Testing topic for testing options.
Aids in the assessment of acetaminophen toxicity
Spectrophotometry
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
Qualitative High Performance Liquid Chromatography-Tandem Mass Spectrometry
Aids in assessment of the etiology of anion gap acidosis
Spectrophotometry
Toxic level: ≥31 mg/dL
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
Qualitative Enzyme Immunoassay/Quantitative Liquid Chromatography-Tandem Mass Spectrometry
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
Qualitative Enzyme Immunoassay/Quantitative Liquid Chromatography-Tandem Mass Spectrometry
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
Qualitative Enzyme Immunoassay/Quantitative Gas Chromatography-Mass Spectrometry
Preferred test to follow up presumptive results
For general screening, Opiates, Urine Screen with Reflex to Quantitation (2005093) is preferred
Quantitative Liquid Chromatography-Tandem Mass Spectrometry
Use to monitor patient adherence
For follow-up testing of a presumptive result, Opiates, Urine, Quantitative (0090364) is preferred
Qualitative Enzyme Immunoassay
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
Qualitative Enzyme Immunoassay/Quantitative Liquid Chromatography-Tandem Mass Spectrometry
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
Qualitative Enzyme Immunoassay/Quantitative Liquid Chromatography-Tandem Mass Spectrometry
Use to monitor cyanide exposure
Quantitative High Performance Liquid Chromatography-Tandem Mass Spectrometry
Use to diagnose increased carbon monoxide (CO) levels and CO poisoning
Spectrophotometry
Note: Refer to ARUP Consult’s Therapeutic Drug Monitoring topic for testing options.
Note: Refer to ARUP Consult’s Nicotine Exposure and Metabolites topic for more testing options.
Use to detect exposure
Quantitative Liquid Chromatography-Tandem Mass Spectrometry
Quantitative Gas Chromatography-Mass Spectrometry/Quantitative Liquid Chromatography-Tandem Mass Spectrometry
Use to monitor patient adherence
Quantitative High Performance Liquid Chromatography-Tandem Mass Spectrometry
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)
Quantitative Liquid Chromatography-Tandem Mass Spectrometry
Note: Refer to ARUP Consult’s Trace Elements–Deficiency and Toxicity topic for testing options.
References
Goldfrank's Toxicologic Emergencies
Hoffman R, Howland M, Lewin N, et al. Goldfrank's Toxicologic Emergencies. 10th ed. McGraw-Hill Education/Medical; 2014.
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Wu AH, McKay C, Broussard LA, et al. National academy of clinical biochemistry laboratory medicine practice guidelines: recommendations for the use of laboratory tests to support poisoned patients who present to the emergency department. Clin Chem. 2003;49(3):357-379.
Medical Experts
Johnson-Davis

McMillin

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