Abstract

Compared to the standard practice of measuring u5-HIAA, measuring fasting p5-HIAA represents a more convenient and accurate way of detecting changes in 5-HIAA levels and provides for an easier and expedited sample collection procedure. Changes in fasting p5-HIAA upon administration of LX1033 were highly correlated with changes in u5-HIAA (p<0.001) with r values suggesting moderate correlation. Fasting p5-HIAA levels displayed less variability than u5-HIAA. Results from this study indicate that fasting p5-HIAA determination can provide a suitable and more patient convenient and compliant alternative to 24-hour u5-HIAA determination.