Rapid Clozapine Blood Level Determination in a National Health Service Trust

AIMS: The use of clozapine demands regular monitoring of patients’ clozapine blood levels. Assays are usually performed in a central laboratory with results available only after several days. The South London and Maudsley NHS Trust wanted to implement a clozapine Point-of-Care (POC) capillary blood test that would provide the benefits of immediate results. METHODS: The MyCare Insite, a small (2.2 kg) tabletop analyser was used. The Insite can readily be connected to electronic health records. Insite device has been fully validated but to achieve the benefit of clozapine POC testing, other factors beyond the test validation needed to be considered. We developed tools, software, and processes to guide health professionals on why and when to measure clozapine blood levels, on what to do with test results, and systems for documentation and tracking of patients’ test results. In addition, the device supplier conducted staff training to ensure consistent and correct testing. Finally, users were certified as qualified based on demonstrated proficiency. RESULTS: We have fully implemented POC capillary clozapine testing across four geographic sites.. Patients and staff preferred capillary finger stick testing over venous draws. Patients’ engagement with their results was better than with laboratory testing. Real-time testing for adherence was possible for patients admitted on clozapine. It was also possible to make rapid dose adjustments based on near immediate plasma level results. Patient safety was increased since toxic levels could be quickly detected. Clinical decision-making was expedited as results were available immediately (< 7 minutes). The utility of the testing meant that the length of hospital stays was reduced as discharges were not delayed pending a laboratory result. CONCLUSION: Clozapine POC blood level testing was successfully implemented at our institution achieving the expected benefits of clozapine POC testing with near immediate results. The new process improves clozapine management, patient engagement and reduces inpatient bed stays.