TY - JOUR
T1 - Up in smoke
T2 - Uncovering a lack of evidence for proton pump inhibitors as a source of tetrahydrocannabinol immunoassay false positives
AU - Powers, Jennifer L.
AU - Rasmussen, Natalie N.
AU - Hurst, Dow
AU - Strathmann, Frederick G.
N1 - Funding Information:
Funding sources: We would like to thank the ARUP Institute for Clinical and Experimental Pathology for funding.
Funding Information:
We would like to thank the ARUP Institute for Clinical and Experimental Pathology for funding. We would like to thank the Clinical Toxicology laboratory staff at ARUP Laboratories.
Publisher Copyright:
© 2017 American Academy of Pain Medicine. All rights reserved.
PY - 2018/11/1
Y1 - 2018/11/1
N2 - Objective. It is recommended that positives in immunoassay drug screens be followed up with more specific confirmatory testing. The drug package insert for pantoprazole mentions reports of false-positive urine screening tests for tetrahydrocannabinol in patients receiving proton pump inhibitors, but no method details or data are given, referenced, or found in literature searches. Thus, we investigated this using our laboratory’s assay. Methods. A spiked sample and samples from 32 patients taking a proton pump inhibitor were analyzed using the EMIT II Plus Cannabinoid assay with a 20 ng/mL cutoff. Additionally, we examined urine samples from 50 patients with false-positive or low-positive screens for evidence of a proton pump inhibitor. To determine whether O-desmethyl pantoprazole sulfate, the major metabolite, shares any structural or electrostatic similarity to suggest a basis for cross-reactivity in the immunoassay, we used computational techniques for analyses. Molecular electrostatic potential energy (MEP) maps were calculated for the global minimum conformers, and the maximum common substructure Tanimoto similarity was calculated for the modeled compounds. Results. Neither the spiked sample nor the patient samples were found to screen positive. None of the false-positive or low-positive screens were found to contain a proton pump inhibitor. Computational studies showed very little similarity in shape or electrostatics between the two molecules. Conclusions. We find no supporting evidence of pantoprazole as the cause of false positives in the EMIT II Plus Cannabinoid assay and caution the use of proton pump inhibitors as an explanation for tetrahydrocannabinol immunoassay false positives.
AB - Objective. It is recommended that positives in immunoassay drug screens be followed up with more specific confirmatory testing. The drug package insert for pantoprazole mentions reports of false-positive urine screening tests for tetrahydrocannabinol in patients receiving proton pump inhibitors, but no method details or data are given, referenced, or found in literature searches. Thus, we investigated this using our laboratory’s assay. Methods. A spiked sample and samples from 32 patients taking a proton pump inhibitor were analyzed using the EMIT II Plus Cannabinoid assay with a 20 ng/mL cutoff. Additionally, we examined urine samples from 50 patients with false-positive or low-positive screens for evidence of a proton pump inhibitor. To determine whether O-desmethyl pantoprazole sulfate, the major metabolite, shares any structural or electrostatic similarity to suggest a basis for cross-reactivity in the immunoassay, we used computational techniques for analyses. Molecular electrostatic potential energy (MEP) maps were calculated for the global minimum conformers, and the maximum common substructure Tanimoto similarity was calculated for the modeled compounds. Results. Neither the spiked sample nor the patient samples were found to screen positive. None of the false-positive or low-positive screens were found to contain a proton pump inhibitor. Computational studies showed very little similarity in shape or electrostatics between the two molecules. Conclusions. We find no supporting evidence of pantoprazole as the cause of false positives in the EMIT II Plus Cannabinoid assay and caution the use of proton pump inhibitors as an explanation for tetrahydrocannabinol immunoassay false positives.
KW - Drug screen
KW - False positive
KW - Metabolite
KW - Pantoprazole
KW - Proton Pump Inhibitor (PPI)
KW - Tetrahydrocannabinol (THC)
UR - http://www.scopus.com/inward/record.url?scp=85056272599&partnerID=8YFLogxK
U2 - 10.1093/pm/pnx266
DO - 10.1093/pm/pnx266
M3 - Article
C2 - 29126183
AN - SCOPUS:85056272599
SN - 1526-2375
VL - 19
SP - 2196
EP - 2200
JO - Pain Medicine (United States)
JF - Pain Medicine (United States)
IS - 11
ER -