Myelofibrosis is a chronic disease, mostly affecting elderly people, in which normal blood production is deregulated. In absence of a potent targeted therapy to treat these patients, patients currently suffer from scarring of the bone marrow, increased spleen size, and symptoms related to the altered blood production, including easy bruising and easy bleeding. Furthermore, patients are at risk of cardiovascular events and transformation of the disease into an aggressive leukemia. Currently, the most targeted therapy for myelofibrosis is Ruxolitinib, a targeted JAK inhibitor. Despite that this drug reduces symptoms and extends life span, not every patient responds to it, resistance can develop during treatment, and most importantly: it does not target the diseased cells. A method to find targeted therapies for blood diseases is pharmacoscopy. In short, the method enables screening of a drug panel in a patient’s own blood, thereby including both the diseased and healthy cells present in a patient. Response to treatments is determined using high-throughput automated imaging, enabling distinction between responses on healthy and diseased cells. Selecting drugs that selectively kill diseased cells while sparing healthy cells present in a patient, has proven to allow for an improved prediction of response of a patient to therapies.