Nevertheless, it has been argued that “from an ethical point of view, it is highly questionable whether leukopenia/pancytopenia should be accepted in patients where screening for TPMT prior to thiopurine therapy can definitively identify TPMT deficiency, which leads in 100% of cases to hematotoxicity under standard dosage of thiopurines” 38. Here, TPMT is linked to Decreased total leukocyte count.