Quantitative Antipsychotic Blood Levels at the Point of Care

Acceptability of point of care testing for antipsychotic medication levels in schizophrenia

Atkins M, Taylor D, Harland R, Brewer A, Williams S, Chesney E, McGuire P. Psych Research Com. 2022 https://doi.org/10.1016/j.psycom.2022.100070

ABSTRACT

We surveyed 106 patients with schizophrenia who were being treated with either oral clozapine or oral aripiprazole. For each patient, the plasma level of the medication was measured using i) a venous blood sample and a conventional lab-based assay and ii) a novel point of care assay that used a capillary blood sample taken with a fingerprick. Immediately after providing the two samples, participants completed a brief questionnaire. We also surveyed 10 members of staff who were directly involved in the care of these patients. 98% of patients found the capillary point-of-care approach acceptable, and 85% preferred it to the conventional venous blood procedure. 78% of patients said it was

useful to have access to the result at the point of care (as opposed to at a later date), and 90% felt that POC testing improved clinical care. 83% said that the POC test made them feel more involved in their treatment. 100% of staff said their experience with the POC test was good, that it was easier than venous collection, and that it was very useful to receive the medication level while the patient was still in the clinic.

Clozapine blood level assessment using a point-of-care device: feasibility and reliability

Kamhi-Nesher S, Taub S, Halimi S, Frenkel M, Azam M, Bormant G, Isakov H, Radzinsky D, Weizman A, Krivoy A. Ther Adv Psychopharmacol. 2022 Jun 14;12:20451253221094435.

ABSTRACT

BACKGROUND: Therapeutic drug monitoring (TDM) is useful to assess clozapine adherence and optimize treatment. However, analysis of venous blood levels by liquid chromatography tandem mass spectrometry (LC-MS/MS) is often logistically complicated and process time is prolonged. OBJECTIVE: To assess the feasibility and reliability of a new point-of-care device, (MyCare™ Insite), using capillary blood for clozapine therapeutic monitoring. METHODS: Matched venous and capillary blood samples were collected from patients treated with clozapine on a stable dose. Samples were analyzed by LC-MS/MS and MyCare Insite Clozapine Test. Clozapine plasma levels were compared between methods using linear regression model. Both patients and treatment team completed questionnaires about the feasibility of blood sampling. RESULTS: Of the total sample (44 patients, 61% males, mean age 43 ± 12 years), mean daily clozapine dose was 293 ± 134 mg/day. Linear regression model demonstrated high correlation with R (2) = 0.83 (p < 0.0001) and mean difference of 26 ± 162 ng/ml. More than 60% of the patients found the clozapine TDM to be important. Most of the participants (58%) favored the capillary sampling and 11% claimed that testing method would affect their adherence to TDM. Moreover, a larger portion (72%) strongly preferred to be tested at the office rather than at the lab. CONCLUSIONS: The point-of-care device offers an accessible and satisfactory measurement of clozapine blood levels. Both patients and healthcare providers reported preference for capillary sampling as well as for the in-office TDM procedure. The immediate results provided by the device can facilitate rapid and informed clinical decisions and therefore improve clozapine treatment outcomes.

First Use of Clozapine Point of Care Testing in Acute Inpatient Psychiatry: Preliminary Report

Boland X, Dratcu L. J Psychiatr Pract. 2022 Jan 6;28(1):62-66.

ABSTRACT

Clozapine is the antipsychotic of choice in treatment-resistant schizophrenia. Serum clozapine concentration testing is essential to monitor adherence, adjust dosing, and ensure treatment safety. However, patients who are acutely unwell are frequently reluctant to undergo blood testing requiring venipuncture. Also, conventional laboratory-based measurement of clozapine plasma levels can take days, thus contributing to the suboptimal use of clozapine when it is most needed. We pioneered clozapine whole-blood point of care (POC) testing in the acute inpatient setting in the treatment of a group of actively psychotic patients receiving clozapine during the outbreak of the COVID-19 pandemic. POC clozapine testing using automated homogenous immunoassay requires only finger prick blood sampling and is more acceptable to patients. As it produces results in minutes, clozapine POC testing serves to promptly ascertain adherence with treatment and inform therapeutic dosing. POC testing offered a more practical, less invasive, and quicker alternative to conventional methods of monitoring clozapine levels. Near immediate availability of clozapine levels expedited clinical decisions and helped ensure safe clozapine prescribing to our severely psychotic patients in a time of crisis. By facilitating patients’ early safe discharge from the hospital, clozapine POC testing also reduced length of hospitalization.