The treatment of immune thrombocytopenia (ITP) can be challenging. The immature platelet count (IPF) can be used in ITP as a supportive information to assess whether the treatment mechanism is having an effect: To have a supportive parameter to answer the clinical question as to whether the observed increase in the platelet count is due to increased platelet production or inhibition of antibody-mediated platelet destruction. Due to the higher reactivity and haemostatic potential of immature platelets, an increased immature platelet count was also found to be associated with a lower risk of bleeding with severely thrombocytopenic patients.