Recommendations for the Use of Laboratory Tests to Support Poisoned Patients Who Present to the Emergency Department
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Clinical Chemistry 49:3 357–379 (2003) Special Report 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 Alan H.B. Wu,1* Charles McKay,2 Larry A. Broussard,3 Robert S. Hoffman,4 Tai C. Kwong,5 Thomas P. Moyer,6 Edward M. Otten,7 Shirley L. Welch,8 and Paul Wax9 Background: Exposure to drugs and toxins is a major who provide clinical toxicology services. For drugs-of- cause for patients’ visits to the emergency department abuse intoxication, most ED physicians do not rely on (ED). results of urine drug testing for emergent management Methods: Recommendations for the use of clinical lab- decisions. This is in part because immunoassays, al- oratory tests were prepared by an expert panel of ana- though rapid, have limitations in sensitivity and speci- lytical toxicologists and ED physicians specializing in ficity and chromatographic assays, which are more de- clinical toxicology. These recommendations were posted finitive, are more labor-intensive. Ethyl alcohol is on the world wide web and presented in open forum at widely tested in the ED, and breath testing is a conve- several clinical chemistry and clinical toxicology meet- nient procedure. Determinations made within the ED, ings. however, require oversight by the clinical laboratory. Results: A menu of important stat serum and urine Testing for toxic alcohols is needed, but rapid commer- toxicology tests was prepared for clinical laboratories cial assays are not available. The laboratory must pro- vide stat assays for acetaminophen, salicylates, co-oxim- etry, cholinesterase, iron, and some therapeutic drugs, such as lithium and digoxin. Exposure to other heavy 1 Department of Pathology and Laboratory Medicine, Hartford Hospital, metals requires laboratory support for specimen collec- Hartford, CT 06102. 2 Department of Emergency Medicine, Medical Toxicology, Hartford Hos- tion but not for emergent testing. pital, Hartford, CT 06102. Conclusions: Improvements are needed for immunoas- 3 Department of Clinical Laboratory Sciences, Louisiana State University says, particularly for amphetamines, benzodiazepines, Health Sciences Center, New Orleans, LA 70112. opioids, and tricyclic antidepressants. Assays for new 4 Department of Emergency Medicine, Bellevue Hospital Center, New York, NY 10016. drugs of abuse must also be developed to meet changing 5 Department of Pathology and Laboratory Medicine, University of Roch- abuse patterns. As no clinical laboratory can provide ester Medical Center, Rochester, NY 14642. services to meet all needs, the National Academy of 6 Department of Laboratory Medicine and Pathology, Mayo Clinic, Roch- ester, MN 55905. Clinical Biochemistry Committee recommends estab- 7 Department of Emergency Medicine, University of Cincinnati Hospital, lishment of regional centers for specialized toxicology Cincinnati, OH 45267. testing. 8 Department of Pathology, Kaiser Permanente Regional Laboratory, Clackamas, OR 97015. © 2003 American Association for Clinical Chemistry 9 Department of Medical Toxicology Good Samaritan Regional Medical Center, Phoenix, AZ 85006 Preamble * Committee Chairman. Address for correspondence: Department of Pathology and Laboratory Medicine, Hartford Hospital, Hartford, CT 06102. This is the ninth in the series of Laboratory Medicine Received May 31, 2002; accepted October 11, 2002. Practice Guidelines sponsored by the National Academy 357 358 Wu et al.: NACB Guidelines for Testing of Poisoned Patients of Clinical Biochemistry (NACB).10 An expert Committee whereas “B” indicates either no consensus or that the of emergency department (ED) physicians and clinical recommendation was not applicable to all situations. laboratory medicine toxicologists was assembled and pre- pared recommendations on the use of clinical laboratory Introduction and Needs Assessment tests to support the diagnosis and management of the Data from the Drug Abuse Warning Network (DAWN) poisoned patient who presents to the ED. Excluded from have shown that a significant number of ED visits are these discussions were drug testing conducted for the associated with the presence of alcohol and drugs as workplace, forensic and medical examiner toxicology, indicated by history (2). Table 1 lists results for 2002. The athletic drug testing, and testing for various compliance statistics refer to patients 6–97 years of age whose pri- programs (e.g., criminal justice, psychiatric, and physician mary presenting problem was associated with drug use health). Many of these other programs are guided by but was not necessarily the sole reason for the ED visit. other recommendations and regulations, such as the Sub- This database is not a measure of illicit drug or substance stance Abuse and Mental Health Services Administration, abuse prevalence in the general population. Moreover, the American Academy of Forensic Sciences, and the these statistics are based on self-reporting by the user and International Olympic Committee. Recommendations for were not necessarily confirmed by laboratory testing. detection of drugs in pregnant women and newborns Some drugs (e.g., cocaine and heroin) may have a higher exposed during the intrauterine period are discussed in a association with ED visits than others because they pro- previous NACB guidelines (1). Some of the recommen- duce greater acute toxicity. Alcohol is not tabulated dations contained here are directed specifically toward separately by DAWN; however, many studies have dem- manufacturers of toxicology reagents. It is hoped that onstrated a high prevalence of alcohol and substance documentation of a clinical need for modified assays will abuse in ED patients, particularly trauma patients. Prev- encourage manufacturers to develop these new and im- alence rates of ϳ25%, along with other data, suggest that proved assays. nearly 30 million ED visits per year could be associated These recommendations were presented in open forum with some form of drug use (3). at several meetings during the year 2001: a local clinical There are other substances that can contribute to sig- chemistry section meeting at the Royal Brisbane Hospital nificant acute clinical problems for which laboratory test- (Brisbane, Australia) in January; the Midwest Association ing might play an important role. Some of these are for Toxicology and Therapeutic Drug Monitoring, Wil- tabulated each year by the Toxic Exposure Surveillance liam Beaumont Hospital (Royal Oak, MI), in May; System of the American Association of Poison Control Edutrak Sessions at the AACC Annual Meeting (Chicago, Centers (4). In 2000, for example, there were 13 000 IL) in August; and in October, The North American reported exposures to organophosphorus compounds, Congress of Clinical Toxicology (Montreal, Canada), The 16 000 to rodenticides (anticoagulants), 12 500 to heavy Society of Forensic Toxicology (New Orleans, LA), and metals, 17 000 to carbon monoxide, and 1000 to toluene. It the Scientific Assembly Toxicology Section meeting of the should be noted that the majority of these exposures were American College of Emergency Physicians (Chicago, IL). Participants at each meeting discussed the merits of the recommendations. A summary of these discussions are Table 1. Estimated number of ED drug episodes and drug presented herein. mentions, 2001.a These guidelines cover four major areas. The section on % of total each recommendation contains background information Drug or class ED visits and summarizes the discussions by the Committee and Alcohol-in-combination 0.218 participants of the various sessions on the rationale for Cocaine 0.193 that recommendation. We also provide qualitative ratings Marijuana/hashish 0.111 for the degree of consensus for adoption of the recom- Benzodiazepines (alprazolam, diazepam, lorazepam, 0.103 clonazepam, triazolam) mendations, based on discussions among the participants Analgesics (acetaminophen, aspirin, ibuprofen, 0.099 at the various presentations and correspondence received: propoxyphene, oxycodone, hydrocodone) “A” indicates general consensus by most participants, Heroin/morphine 0.093 Amphetamines (amphetamine and methamphetamine) 0.034 Barbiturates (phenobarbital, over-the-counter sleep 0.018 10 Nonstandard abbreviations: NACB, National Academy of Clinical Bio- aids) chemistry; ED, emergency department; DAWN, Drug Abuse Warning Net- TCAs (amitriptyline, doxepin, imipramine) 0.012 work; NPIS, National Poisons Information Service; ACB, Association of PCP 0.006 Clinical Biochemists; TCA, tricyclic antidepressant; LSD, lysergic acid diethyl- Lithium 0.003 amide; GHB, ␥-hydroxybutyrate; TAT, turnaround time; POC, point-of-care; GC, gas chromatography; MS, mass spectrometry; PCP, phencyclidine; THC, GHB 0.003 tetrahydrocannabinol; FDA, Food and Drug Administration; QA, quality LSD 0.003 assurance; QC, quality control; CNS, central nervous system; PT, prothrombin a From the Office of Applied Statistics, the DAWN, 2001. Total ED visits, 100.5 time; EPP, erythrocyte protoporphyrin; TIBC, total iron-binding capacity; million; number of drug episodes, 638 484; drug mentions, 1 165 367. UIBC, unsaturated iron-binding capacity; and RBC, red blood cell. Clinical Chemistry 49, No. 3, 2003 359 managed in a non-healthcare facility, usually at the site of Table 2. Stat quantitative serum toxicology assays required exposure. to support an ED.a There will always be pressure between the need to Acetaminophen (paracetamol) make