Reliable, Scalable Assessment in Routine Practice-Implementing Rapid Clozapine Blood Levels in the Real World

It is well documented that clozapine is under-utilized in the US, even though it is the most effective medication for treatment-resistant schizophrenia. In addition, clinical assessments of a patient's drug status have been proven inaccurate. Therapeutic drug monitoring (TDM) can be an effective tool for assessing the patient's status in various clinical settings. Testing blood levels using liquid chromatography with mass spectrometry, either by sending out or running in-house, is not rapid enough to be of clinical benefit in most situations. Receiving blood levels within hours provides vital information to improve patient management. We expected that implementing a novel FDA cleared clozapine immunoassay that provides blood levels within hours would benefit patient care. The goal of this project was to implement rapid clozapine blood level testing. Justifications to administration, laboratory personnel, and psychiatry prescribers were created and presented. Upon agreement and implementation of the rapid testing, training on utilizing blood levels and potential changes to patient workflow was presented to the Department of Psychiatry. Since implementing the clozapine immunoassay, the time to receive the test result improved from an average of 87.4 hours to 4.2 hours allowing changes in re-initiation protocols, avoidance of harm, increased utilization of TDM in different clinical scenarios, and alterations in discharge planning. Rapid clozapine blood levels have improved patients' access to clozapine by increasing prescriber confidence by providing critical blood level information in a clinically relevant timeframe.