Accuracy of radiographer comment following a two-month experiential and blended learning in appendicular skeleton X-ray interpretation: The Singapore experience.

INTRODUCTION: The value of combined blended and experiential learning on radiographer diagnostic comment has not been explored. This study aims to examine the accuracy of image interpretation comment of radiographers who received a period of blended and experiential learning in Radiographer Abnormality Detection Systems (RADS). METHODS: We evaluated the diagnostic opinions of 13 radiographers who received a blended training and experiential learning (a process of self-learning and reflection) in RADS. Radiographers' opinions on 16,483 images were examined using the final radiologists' report as a reference standard. For each radiographer, we recorded the number of true positive, true negative, false positive and false negative opinions and MedCal® was used to calculate diagnostic performance and error rates. A t-test was used to assess whether the number of images read was associated with performance and whether the radiographers retained performance over time. RESULTS: Sensitivity ranged from 87.4 (84.0-90.2) to 98.9 (97.5-99.7) with a mean of 94.3 (93.6-94.8). Specificity varied from 96.4 (94.8-97.5) to 99.9 (99.41-100.0) with a mean of 98.2 (97.9-98.4). Diagnostic accuracy ranged from 93.1 (91.5-94.4) to 99.5 (98.9-99.8) with a mean of 96.9 (96.6-97.1). The mean false positive rate was 0.018 (range: 0.010-0.031) with a false negative rate of 0.057 (range: 0.026-0.11). There were no differences in performance between the first and latter nine months of providing opinions and the number of images reviewed was not associated with performance. CONCLUSION: Radiographers who received blended and experiential learning in RADS provide accurate diagnostic comments on plain emergency appendicular skeleton radiographs. IMPLICATION FOR PRACTICE: A combined blended and experiential learning can equip radiographers to provide diagnostic opinion on plain appendicular skeleton radiographs.

Population pharmacogenetic-based pharmacokinetic modeling of efavirenz, 7-hydroxy- and 8-hydroxyefavirenz.

The purpose of this study was to determine the demographic and pharmacogenetic covariates that influence the disposition of efavirenz (EFV) and its major metabolites. A population pharmacokinetic (PK) model was developed from a randomized, cross-over, drug-interaction study in healthy male Korean subjects (n = 17). Plasma concentrations of EFV and its hydroxy-metabolites (0-120 hours) were measured by LC/MS/MS. Genomic DNA was genotyped for variants in the cytochrome P450 (CYP) 2A6, 2B6, 3A5, and MDR1 genes. A PK model was built in a stepwise procedure using nonlinear mixed effect modeling in NONMEM 7. The covariate model was built using the generalized additive modeling and forward selection-backward elimination. Model-based simulations were performed to predict EFV steady-state concentrations following 200, 400, and 600 mg daily oral dose among different CYP2B6 genotypes. The final model included only CYP2B6 genotype as a covariate that predicts EFV clearance through the formation of 8-OH EFV that represented 65% to 80% of EFV clearance. The total clearance of EFV in CYP2B6*6/*6 genotype was ∼30% lower than CYP2B6*1/*1 or CYP2B6*1/*6 alleles (P < .001). Clopidogrel reduced both formation and elimination clearances of 8-OH EFV by 22% and 19%, respectively (P = .033 and .041). Other demographics and genotype of accessory CYP pathways did not predict EFV or metabolites PK. CYP2B6 genotype was the only significant predictor of EFV disposition. The developed model may serve as the foundation for further exploration of pharmacogenetic-based dosing of EFV.