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Comparison of serum and whole blood concentrations in quetiapine overdose cases


This study aimed to compare whole blood and serum concentrations of quetiapine in acute poisoning cases. Authentic whole blood and respective serum samples were routinely collected from patients diagnosed with blood poisoning at our University Hospital. Accordingly, whole blood and serum paired samples from nine patients (one male and eight female patients) were analyzed for quetiapine using liquid chromatography-mass spectrometry (LC–MS). Quetiapine concentrations in whole blood and serum samples ranged widely from 5.4 to 2780 ng/mL and 9.9 to 2500 ng/mL, respectively. The whole blood/serum concentration ratio was 0.5–1.1 and increased together with an increase in whole blood and serum quetiapine concentrations. The ratio was reversed at around 2500 ng/mL to > 1. Our findings suggest that whole blood concentrations are more useful than serum concentrations in diagnosing quetiapine poisonings.

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This work was supported by JSPS KAKENHI Grant Numbers JP17K09278. The authors would like to thank Enago ( for the English language review.

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Correspondence to Takeshi Saito.

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The authors declare no conflict of interest associated with this manuscript.

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This study was approved by the Ethics Committee of Tokai University School of Medicine, and informed consent was obtained from all patients prior to study participation (17R 028).

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Saito, T., Tsuji, T., Namera, A. et al. Comparison of serum and whole blood concentrations in quetiapine overdose cases. Forensic Toxicol 40, 403–406 (2022).

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  • Acute quetiapine poisoning
  • Therapeutic drug concentrations
  • Whole blood/serum concentration ratios
  • Diagnosis