Point-of-care (POC) technology is increasingly available, with one device approved for hematological monitoring, and another submitted for review to obtain plasma levels of clozapine and five other antipsychotics. There is one POC CBC device currently approved in the U.S. This was approved after testing demonstrated absolute neutrophil count and white blood cell values equivalent to an automated hematology analyzer. The device can be operated by trained personnel, including nurses, medical assistants, or other designed staff. The device provides flexibility in the time and place of ANC testing, and requires a drop of blood from a finger-prick, a feature rated by patients as less painful than venipuncture. The results are available in about five minutes, and the manufacturer has created an integrated network to register patients with REMS so that results are simultaneously transmitted to the clozapine monitoring registry, the prescriber and the pharmacy. In addition, there is a different POC device from Saladax Biomedical to assess antipsychotic levels. It is approved in other countries, but currently not available in the U.S.
Monitoring of plasma clozapine levels can be useful during titration, when there are adherence questions, when unusual adverse effects crop up, or after changes in concurrent medications or smoking status. Unfortunately, plasma level results are not available from commercial labs for 1 to 2 weeks in many instances. The availability of real time clozapine plasma levels could allow clinicians to make accurate and timely decisions about dose adjustments.