Therapeutic International Normalized Ratio Monitoring

studies have shown that the percentage of ring sideroblasts in MDS is not prognostically important. Thus, in the revised WHO classification, a diagnosis of MDS-RS may be made even in the presence of only 5% of ring sideroblasts in cases with SF3B1 mutation. MDS-RS cases will be subdivided into cases with single lineage dysplasia (previously classified as RARS) and cases with multilineage dysplasia (previously classified as refractory cytopenia with multilineage dysplasia). Furthermore, RARS-T has been accepted as an entity and termed MDS/ myeloproliferative neoplasm (MPN) with ring sideroblasts and thrombocytosis (MDS/MPN-RS-T) in the 2016 classification. Unlike MDS-RS, the number of ring sideroblasts required for a diagnosis of MDS/MPN-RS-T is 15%, irrespective of the presence or absence of a SF3B1 mutation [4]. As described in the case of Narang et al., in a young female of 18 years old without a history of persistent refractory cytopenia(s), a diagnosis of MDS can only be established after exclusion of secondary causes such as nutritional deficiencies [1]. An adequate trial with hematinics (vitamin B12, folic acid, and pyridoxine) is needed in such cases. After exclusion of secondary causes, if cytopenia(s) still persists, a repeat bone marrow examination with cytogenetic and molecular studies can be considered to establish the diagnosis of a clonal hematopoietic disease such as MDS or MDS/MPN.