Miniature mass spectrometer–based point-of-care assay for measuring three psychiatric drugs in human plasma and whole blood

Developing a rapid, simple method to detect psychiatric drug concentrations is essential, as it facilitates long-term monitoring of treatment efficacy and is critical for managing drug poisoning in clinical settings due to abuse or accidental overdose. Conventional laboratory-based assays used for monitoring psychiatric medications often demonstrate prolonged processing times, leading to considerable delays in adjusting treatment regimens. To address this, this study introduced a point-of-care testing (POCT) approach using a miniature mass spectrometer, which allows for rapid and precise measurement of three

psychiatric drugs including carbamazepine (CBZ), quetiapine (QTP), and olanzapine (OLZ) in human plasma and whole blood. Quantification is achieved through the use of paper capillary spray combined with miniature mass spectrometry, within the clinically relevant concentration range for three drugs.

This study presented the first quantitative POCT using a miniature mass spectrometer coupled with an ambient ionization method to measure the concentrations of three psychiatric drugs in human plasma and whole blood. The assay requires only a small volume of bodily fluid (50 µl of plasma) and has a turnaround time of under 2 min. Good linear relationships are obtained between responses and concentrations within the clinically relevant concentration range. Additionally, the study demonstrated the feasibility of using miniature MS systems for on-site analysis to measure drug concentrations in spiked samples. This approach provides faster analysis and requires minimal sample preparation, making it ideal for on-site clinical use, offering immediate results for both clinicians and psychiatric patients. We believe that these initiatives provide a foundation for (i) the implementation of POCT using miniature MS to measure CBZ, QTP, and OLZ in clinical patient samples; (ii) the expansion of MS-based assays to include other long-acting therapies for monitoring adherence; and (iii) the diagnosis and adjunctive treatment of psychiatric drug poisoning resulting from abuse or accidental overdose.