Impact of Heat Inactivation of Blood Samples on Therapeutic Drug Monitoring of 5 Second-Generation Antipsychotics and Their Metabolites

Background: The severe acute respiratory syndrome coronavirus 2 outbreak has been classified as a pandemic. Because many coronaviruses are heat sensitive, heat inactivation of patient samples at 56 degrees C before testing reduces the risk of transmission. The aim of this study is to assess the impact of heat inactivation of patient blood samples on plasma concentrations of 5 second-generation antipsychotics and their metabolites. Methods: Blood samples were collected during routine clinical therapeutic drug monitoring examination between April 3, 2021, and April 19, 2021. Samples were divided into 2 groups: group A, noninactivated raw sample, and group B, inactivated samples. Inactivation was performed by a 30-minute incubation at 56 degrees C. The levels of the 5 drugs and their metabolites before and after sample heat inactivation were measured using liquid chromatography-tandem mass spectrometry and compared. Furthermore, correlation and Bland-Altman analyses were conducted. Results: No statistically significant difference was observed between the levels of the 5 drugs and their metabolites (ie, risperidone, 9-OH-risperidone, aripiprazole, dehydroaripiprazole, olanzapine, quetiapine, norquetiapine, clozapine, and norclozapine) in the noninactivated group A and the inactivated group B (P > 0.05). Each drug's concentration values in inactivated and noninactivated treatments correlated (Spearman r(s) > 0.98; P < 0.001). The results of the noninactivated treatment methods and samples alone showed good consistency via Bland-Altman analysis. Conclusions: Blood sample heat inactivation had no significant effect on the therapeutic drug monitoring of 5 second-generation antipsychotics and their metabolites. This inactivated treatment method should be recommended to effectively protect laboratory staff from virus contamination.