Assessment of riboflavin as a tracer substance: Comparison of a qualitative to a quantitative method of riboflavin measurement

Quantitative fluorometric assessment is superior to qualitative visual inspection alone in determining medication adherence. The combination of 25-50 mg of daily riboflavin and a cut-off level of 900 ng/mL allows for the acceptable sensitivity of missing detection of non-compliant participants while preserving a high level of power to detect all cases of medication compliance.