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Lysergic acid diethylamide (LSD) is an extremely potent psychedelic ergot alkaloid derived from the fungus, Claviceps purpurea.(1) The drug LSD binds to serotonin receptors in the central nervous system and acts as a serotonin agonist.
The clearance half-life of LSD averages 3 to 4 hours. It takes 5 to 7 half-lives to clear 98% of a drug dose. Therefore, the presence of LSD greater than the lower limit of quantification (LOQ; cutoff concentration) indicates exposure to LSD within 1 day.(2)
LSD is metabolized to 2-oxo-3-hydroxy-LSD, which is present at concentrations 16 to 43 times higher than LSD, and is likely to be present in urine for up to 4 days after last exposure.(3,4)
Confirming use of lysergic acid diethylamide
Lysergic acid diethylamide (LSD) exposure is confirmed if LSD is present >0.5 ng/mL or if 2-oxo-3-hydroxy-LSD is present >5.0 ng/mL.
The liquid chromatography-tandem mass spectrometry test is not subject to any known interference.
LSD BY LC-MS/MS
2-OXO-3-HYDROXY-LSD BY LC-MS/MS
1. Babu KM, Ferm RP: Hallucinogens. In Goldfrank's Toxicologic Emergencies. Edited by Flomenbaum, Goldfrank, Hoffman, Howland, Lewin, and Nelson. Eighth edition. New York. McGraw-Hill Book Company, 2006 pp 1202-1211
2. Baselt RC: Lysergic Acid Diethylamide. In Dispositition of Toxic Drugs and Chemical in Man, Edited by RC Baselt. Eighth edition. Foster City, CA. Biomedical Publications, 2008 pp 871-874
3. Johansen SS, Jensen JL: Liquid chromatography-tandem mass spectrometry determination of LSD, ISO-LSD, and the main metabolite 2-oxo-3-hydroxy-LSD in forensic samples and application in a forensic case. J Chromatogr B Analyt Technol Biomed Life Sci 2005;825:21-28
4. Klette KL, Anderson CJ, Poch GK, et al: Metabolism of lysergic acid diethylamide (LSD) to 2-oxo-3-hydroxy LSD (O-H-LSD) in human liver microsomes and cryopreserved human hepatocytes. J Anal Toxicol 2000;24:550-556