Clinical Utility of an LC-MS/MS Seizure Panel for Common Drugs Involved in Drug-Induced Seizures

• Published in: Clinical chemistry (Baltimore, Md.) Vol. 55; no. 1; pp. 126 - 133
• Main Authors: Drees, Julia C, Stone, Judy A, Olson, Kent R, Meier, Kathryn H, Gelb, Alan M, Wu, Alan H. B
• Format: Journal Article
• Language: English
• Published: Washington, DC Am Assoc Clin Chem 01.01.2009; American Association for Clinical Chemistry; Oxford University Press
• Subjects: Adult; Aged; Analytical chemistry; Analytical, structural and metabolic biochemistry; Biological and medical sciences; Chromatography; Chromatography, Liquid; Control systems; Drug Monitoring; Drug-Related Side Effects and Adverse Reactions; Female; Fundamental and applied biological sciences. Psychology; Humans; Investigative techniques, diagnostic techniques (general aspects); Liquid chromatography; Male; Mass spectrometry; Medical sciences; Middle Aged; Patients; Pharmaceutical Preparations - blood; Plasma; Poisons; Primary care; Seizures - blood; Seizures - chemically induced; Sensitivity and Specificity; Solid Phase Extraction; Studies; Tandem Mass Spectrometry; Toxicology; Drug; Nervous system diseases; Coupled method; Biochemistry; Liquid chromatography; Epilepsy provoked by; Cerebral disorder; Convulsion; Central nervous system disease; Clinical biology; Neurological disorder; Molecular biology; Mass spectrometry
• ISSN: 0009-9147; 1530-8561
• DOI: 10.1373/clinchem.2008.110858

Approximately 6% of new-onset seizures are drug-related, but there is currently no reliable way to determine if a seizure is drug-induced. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a powerful tool that allows simultaneous detection of numerous analytes of diverse chemical nature in patient samples. This allows a single analysis to incorporate many compounds relevant to a particular clinical presentation, such as suspected drug-induced seizures. We investigated whether results from a seizure panel using LC-MS/MS could affect patient care. We developed a semiquantitative LC-MS/MS assay to detect 12 chemically diverse drugs implicated in drug-related seizures. We collected leftover serum and plasma samples from patients who had seized, performed solid-phase extraction, and analyzed the samples using a hybrid triple quadrupole/linear ion trap mass spectrometer. After assembling a team of medical and toxicology experts, we developed and used a scoring system to determine whether the results of the seizure panel would have affected patient treatment in each case where a drug was detected. In an analysis of 157 samples from patients who seized, 17 (11%) were found to be positive for a drug on the seizure panel. The team of experts determined that the test results probably or definitely would have affected treatment in 7 (41%) of these cases. A test that detects the presence of drugs implicated in drug-induced seizures can help physicians determine if an unexplained seizure is drug-related and thus potentially better direct patient care. Additionally, LC-MS/MS is an effective tool for answering clinically driven questions.