Determination of tacrolimus in human whole blood in kidney transplant recipients using a rapid and specific LC-MS/MS method.

OBJECTIVE: To develop and validate an LC-M/SMS method for the determination of tacrolimus in human whole blood. METHOD: The LC-MS/MS method for the determination of tacrolimus in whole blood was developed and validated according to the guidelines. Concentrations of TAC in 100 kidney transplant patients measured by LC-MS/MS were compared with CMIA using correlation analysis and Bland-Altman plots. RESULTS: The method had a total chromatographic run time of 5 min. The calibration curves were linear over the range of 0.5-100.0 ng/mL with a lower limit of quantification of 1 ng/mL. The intra- and interday accuracy was within the range of 93.3%-109.2% and 96.0%-108.4%, respectively, with precision ranging from 0.8 to 9.4%. The mean extraction recoveries of TAC ranged from 102.6 to 107.8%. The mean concentrations of TAC in whole blood of kidney transplant patients measured by the two assays were different at 1, 3 months and all time points (p < 0.001), but no significant difference was observed at 6 months (p = 0.094). The correlation of data was good with the correlation coefficients (r2 ) of 0.7581, 0.8811, 0.8777, and 0.8077, respectively. Passing-Bablok regression analysis demonstrated good correlations with r2 values higher than 0.88 between TAC levels measured by LC-MS/MS and CMIA. Using Bland-Altman plots yielded average biases of 1.29, 0.79, 0.11, and 0.65 ng/mL at 1, 3, and 6 months and all time points. CONCLUSION: The LC-MS/MS method was validated for the accurate determination of TAC in human whole blood. The comparison of tacrolimus concentrations measured by the LC-MS/MS with CMIA showed a good correlation and agreement of two methods, suggesting LC-MS/MS should be used routinely to monitor TAC concentrations in kidney transplant patients.

The prevalence of dental caries and associated factors among secondary school children in rural highland Vietnam.

BACKGROUND: To determine the prevalence of dental caries in primary and permanent teeth and identify factors associated with dental caries among secondary school children in rural highland Vietnam. METHODS: This was a cross-sectional study that included 1985 secondary schoolchildren. Dental examination was performed at school using World Health Organization criteria. Data collection on demographic characteristics and knowledge, attitude, and practices related to dental caries was conducted by interviewing children. Descriptive and inferential statistics using a multivariate logistic regression model were applied. RESULTS: Prevalence of caries in primary and permanent teeth was 41.1 and 68.9 %, respectively. Prevalence of caries in primary teeth in the age group 11-12 years old (59.4 %) was significantly higher than in children in the age group of 13-14 years (27.8 %; p < 0.01). Factors associated with dental caries in primary teeth were age group of 11-12 years, belonging to the Jarai ethnic group, and having inadequate knowledge or attitude related to dental caries. Factors associated with dental caries in permanent teeth were having insufficient knowledge, attitude, and practices related to dental caries. CONCLUSIONS: The prevalence of dental caries in primary and permanent teeth was high among secondary school children in Vietnam's rural highlands. It is recommended that interventions focus on younger secondary school children and the Jarai minority ethnic group, and that interventions should emphasize improving knowledge, attitudes, and practices related to dental caries.