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

Abstract

Background: Exposure to drugs and toxins is a major cause for patients' visits to the emergency department (ED).Methods: Recommendations for the use of clinical laboratory tests were prepared by an expert panel of analytical toxicologists and ED physicians specializing in clinical toxicology. These recommendations were posted on the world wide web and presented in open forum at several clinical chemistry and clinical toxicology meetings. Results: A menu of important stat serum and urine toxicology tests was prepared for clinical laboratories who provide clinical toxicology services. For drugs-ofabuse intoxication, most ED physicians do not rely on results of urine drug testing for emergent management decisions. This is in part because immunoassays, although rapid, have limitations in sensitivity and specificity and chromatographic assays, which are more definitive, are more labor-intensive. Ethyl alcohol is widely tested in the ED, and breath testing is a convenient procedure. Determinations made within the ED, however, require oversight by the clinical laboratory. Testing for toxic alcohols is needed, but rapid commercial assays are not available. The laboratory must provide stat assays for acetaminophen, salicylates, co-oximetry, cholinesterase, iron, and some therapeutic drugs, such as lithium and digoxin. Exposure to other heavy metals requires laboratory support for specimen collection but not for emergent testing. Conclusions: Improvements are needed for immunoassays, particularly for amphetamines, benzodiazepines, opioids, and tricyclic antidepressants. Assays for new drugs of abuse must also be developed to meet changing abuse patterns. As no clinical laboratory can provide services to meet all needs, the National Academy of Clinical Biochemistry Committee recommends establishment of regional centers for specialized toxicology testing. © 2003 American Association for Clinical Chemistry PreambleThis is the ninth in the series of Laboratory Medicine Practice Guidelines sponsored by the National Academy Clinical Chemistry 49:3 357-379 (2003) Special Report 357of Clinical Biochemistry (NACB). 10 An expert Committee of emergency department (ED) physicians and clinical laboratory medicine toxicologists was assembled and prepared recommendations on the use of clinical laboratory tests to support the diagnosis and management of the poisoned patient who presents to the ED. Excluded from these discussions were drug testing conducted for the workplace, forensic and medical examiner toxicology, athletic drug testing, and testing for various compliance programs (e.g., criminal justice, psychiatric, and physician health). Many of these other programs are guided by other recommendations and regulations, such as the Substance Abuse and Mental Health Services Administration, the American Academy of Forensic Sciences, and the International Olympic Committee. Recommendations for detection of drugs in pregnant women and newborns exposed during the intrauterine period are discussed in a previous NACB guidelines (1 ). Som...

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