LSDU - Clinical: Lysergic Acid Diethylamide (LSD) Confirmation, Urine

Test Catalog

Test Name

Test ID: LSDU    
Lysergic Acid Diethylamide (LSD) Confirmation, Urine

Useful For Suggests clinical disorders or settings where the test may be helpful

Confirming use of lysergic acid diethylamide

Testing Algorithm Delineates situations when tests are added to the initial order. This includes reflex and additional tests.

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

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)

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.


Cutoff concentrations:  



<0.5 ng/mL



<5.0 ng/mL

Interpretation Provides information to assist in interpretation of the test results

Lysergic acid diethylamide (LSD) exposure is confirmed if LSD is present above 0.5 ng/mL or if 2-oxo-3-hydroxy-LSD is present above 5.0 ng/mL.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

The liquid chromatography-tandem mass spectrometry test is not subject to any known interference.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Babu KM, Ferm RP: Hallucinogens. In Goldfrank's Toxicologic Emergencies. Edited by M Flomenbaum, DS Goldfrab, RJ Hoffman, et al. 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

Special Instructions and Forms Library of PDFs including pertinent information and consent forms, specimen collection and preparation information, test algorithms, and other information pertinent to test