Omeros Corporation announced that the Centers for Disease Control and Prevention (CDC) has approved an International Classification of Diseases (ICD-10) diagnosis code, M31.11 – hematopoietic stem cell transplantation-associated thrombotic microangiopathy (HSCT-TMA). The absence of a specific HSCT-TMA diagnosis code has led to underreporting of diagnoses and inaccurate coding, which has complicated reporting of the incidence and outcomes of the disease. This new ICD-10 code, which will be effective October 1, 2021, will for the first time allow clinicians, payers and others to accurately track the incidence of HSCT-TMA. Additional instructions about how to report the code will be available from the CDC later this year. Separately, the Centers for Medicare & Medicaid Services (CMS) has approved two ICD-10-PCS codes for the administration of narsoplimab: XW03357 – Introduction of Narsoplimab Monoclonal Antibody into Peripheral Vein, and XW04357 – Introduction of Narsoplimab Monoclonal Antibody into Central Vein, Percutaneous Approach, New Technology Group 7. ICD-10-PCS codes are used by billers to identify procedures and services performed during an inpatient stay. These new procedure codes will also be effective October 1, 2021. The new codes will be essential to facilitating billing and reimbursement and for tracking utilization, if narsoplimab is approved by the U.S. Food and Drug Administration (FDA). Additional instructions about how to report the code will be available from CMS later this year, and providers should consult their payers for guidance on use of the codes.