False positive paracetamol results due to interference in a colorimetric assay. A case study

Shugo Kawamoto

Research output: Contribution to journalArticlepeer-review


A 31-year-old female with no medical history of liver disease or intake of herbal medicine was admitted to hospital for abdominal pain, decreased appetite, malaise, tea coloured urine and confusion. Routine laboratory testing revealed elevated liver function tests (LFTs) and marked coagulopathy consistent with a diagnosis of acute liver failure (ALF). Plasma paracetamol level at 121 μmol/L prompted clinical consideration of paracetamol drug overdose; however, the patient denied taking paracetamol. Over the course of her hospitalisation general conditions and liver functions improved; however, plasma paracetamol concentration remained greater than 100 μmol/L. This article discusses the case where the colorimetric principle for paracetamol quantification gave rise to a falsely elevated paracetamol, confounding the clinical picture to suggest paracetamol overdose and recommendations for laboratories using the colorimetric principle to help identify this interference.
Original languageEnglish (US)
Pages (from-to)86-89
Number of pages4
JournalNew Zealand Journal of Medical Laboratory Science
Issue number2
StatePublished - Jul 1 2022
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2023-03-07
Acknowledgements: The research reported in this publication was supported by the King Abdullah University of Science and Technology (KAUST) in Thuwal, Saudi Arabia. We are grateful to the sponsors of the Center for Subsurface Imaging and Modeling Consortium for their financial support. For computer time, this research used the resources of the Supercomputing Laboratory at KAUST and the IT Research Computing Group. We thank them for providing the computational resources required for carrying out this work.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.

ASJC Scopus subject areas

  • Clinical Biochemistry


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