Fig. 2
From: Pilot evaluation of an enzymatic assay for rapid measurement of antiretroviral drug concentrations
Comparison between RESTRICT assay and LC–MS/MS TFV-DP measurements. a A priori fluorescence thresholds corresponding to adequate adherence (700 fmol/punch) and perfect adherence (1250 fmol/punch) among men who have sex with men receiving PrEP were interpolated from a standard curve obtained with TFV-DP spiked in blood. b Using the a priori cut-off of 87.2, RESTRICT distinguished samples with TFV-DP concentrations ≥ 700 fmol/punch with 100% sensitivity and 92.9% specificity. c Using the a priori fluorescence threshold of 71.0 corresponding to ≥ 1250 fmol/punch yielded 100% sensitivity and specificity in distinguishing samples with TFV-DP corresponding to perfect adherence. d RESTRICT fluorescence intensities were correlated with LC–MS/MS TFV-DP concentrations. Pearson correlation coefficient r = − 0.845 (CI − 0.941 to − 0.624), p < 0.0001