Hematological clozapine monitoring with a point-of-care device: A randomized cross-over trial

Clozapine remains the drug of choice for patients with treatment-resistant schizophrenia, who show a response rate of about 50% despite their unresponsiveness to other antipsychotics. Although treatment with clozapine can lead to considerable savings on bed days, the drug is under-utilized for several reasons, perhaps most importantly because of the mandatory hematological monitoring. The Chempaq Express Blood Counter (Chempaq XBC) is a point-of-care device providing counts of white blood cells (WBC) and granulocytes based on a capillary blood sampling. A randomized cross-over trial design was used comparing capillary blood sampling using a point-of-care device with traditional venous blood sampling. Patients were randomized to two sequences starting with either capillary or venous blood sampling followed by a repeated sequence. Primary outcome was measured on a 10-cm visual analog scale. Eighty-five patients were included in the test. Eight (9.4%) dropped out before completion. Patients indicated that they found capillary blood monitoring less painful than venous sampling (VAS ratings: 0.55 cm 25-75 percentiles: 0.1-1.4 cm vs. 1.75 cm 25-75 percentiles: 0.7-2.6, p<0.001). They also felt less inconvenienced by the point-of-care method than the traditional blood sampling, which involved traveling to the laboratory clinical (0.3 cm 25-75 percentiles: 0.05-0.7 vs. 2.3 cm 25-75 percentiles: 0.75-4.5, p<0.001). For hematological monitoring of clozapine patients a point-of-care device based on capillary blood sampling is better tolerated than traditional venous blood sampling. (C) 2011 Elsevier B.V. and ECNP. All rights reserved.