In addition, some laboratory findings such as steroid refractory persistent/worsening eosinophilia, leucocytosis, circulating blasts, dysplastic cells, thrombocytopenia or thrombocytosis, anaemia, increase in serum vitamin B12 (>1000 pg/mL, due to the increased production of haptocorrins, which bind to vitamin B12 in serum and various tissues) or in serum triptase (>12 ng/mL) may help in differential diagnosis with malignant subtypes.37 This evidence concerns the gene TCN1 and anemia (phenotype).