Duffy-null-associated absolute neutrophil count (DANC): an audit from south-western Sydney evaluating the neutrophil lower reference range for patients with DANC

Background: Duffy-null red blood cell phenotype (Fy[a-b-]) results from a polymorphism in ACKR1 causing loss of Duffy expression with highest prevalence in individuals of African and Middle Eastern ancestry. Duffy-null-associated absolute neutrophil count (DANC) is frequently misinterpreted as pathological neutropenia, potentially leading to negative impacts on health economics, health equity and patient quality of life. Establishing a reference range for DANC will help mitigate these impacts.