Validation of a HPLC method for the measurement of erythrocyte encapsulated thymidine phosphorylase (EE-TP) activity

► Validated HPLC assay for erythrocyte encapsulated thymidine phosphorylase (EE-TP). ► The method was linear in the range of 5-500 nmol/ml (r2 = 0.992). ► Intra- and inter-day precisions were <9.6 and accuracies were within ±20%. ► Limits of detection and quantification were 1.2 and 10 nmol/ml, respectively. ► Enzyme activity was determined in batches of EE-TP manufactured for clinical use.