Thiopurine S-Methyltransferase Activity in Red Blood Cells by Production of 6-Methylthioguanine Riboside

**Semantic type:** Laboratory Procedure

**Definition:** A quantitative procedure that measures the production of 6-methylthioguanine riboside to determine the activity of thiopurine S-methyltransferase in a red blood cell specimen.

**Synonyms:** - TPMT activity in RBC by production of 6-MTG riboside