Overview

• The International Society of Blood Transfusion granted official status to ‘Gwada Negative’ in June 2025, marking the latest addition to global blood group classifications.
• This blood type is distinguished by a complete absence of the EMM antigen and has so far been identified in only one 68-year-old woman from Guadeloupe.
• Next Generation Sequencing in 2019 enabled researchers to reanalyse a preserved 2011 sample and discover the rare genetic mutation behind the EMM-negative profile.
• The French Blood Establishment is launching targeted donor screenings in Guadeloupe to uncover any additional carriers of this ultra-rare blood group.
• Experts say expanding the known blood group repertoire will enhance transfusion safety and improve care for patients with uncommon blood types.