Duffy null phenotyping reduces unnecessary workup in asymptomatic neutropenia: A quality initiative in a correctional hematology clinic

Abstract Background: Referrals for neutropenia are common in hematology clinics serving the Department of Corrections (DOC) population. Many patients present with asymptomatic mild to moderate neutropenia (absolute neutrophil count [ANC] 500–1500), often undergoing costly and unnecessary evaluations. The Duffy-null phenotype, prevalent in individuals of African and Middle Eastern ancestry, is associated with physiologically lower ANCs and no increased infection risk. Despite evidence supporting its diagnostic utility, Duffy typing is underutilized in clinical practice. Objective: To implement Duffy null phenotyping as a triage tool for asymptomatic neutropenia in a DOC population and assess its clinical and economic impact on diagnostic workup. Methods: An academic medical center's DOC Hematology Clinic has launched a quality improvement initiative. Adult patients hospitalized with asymptomatic mild/moderate neutropenia (ANC 500-1500) received Duffy-null phenotyping and a peripheral smear as a first-line evaluation. Additional testing (e.g., nutritional panels, viral serologies, autoimmune markers, imaging) was reserved for Duffy non-null or symptomatic patients. A Plan-Do-Study-Act (PDSA) paradigm was implemented. De-identified clinical data and cost analysis were collected for three groups: the Duffy-null phenotype with no further workup, the complete conventional workup, and Duffy typing followed by traditional workup for negative patients. IRB approval was obtained. Results: Among the 31 people tested, 41.9% (n=13) were found to have the Duffy-null phenotype and were not subjected to additional testing. The Duffy-first procedure cost $9,300, compared to $77,748 for regular testing, representing an 88% savings. Even with negative occurrences demanding a thorough workup, the total treatment cost $84,413 (only 8.6% more than normal testing). Duffy-null patients were discharged after a single telemedicine follow-up, which reduced clinic load and follow-up visits by more than 40%. Internal and published data reveal that up to 66.7% of Black people have the Duffy-null phenotype, emphasizing the significance of ancestry-specific diagnostic techniques in this setting. Conclusions: Routine use of Duffy null phenotyping in the examination of asymptomatic neutropenia in high-prevalence groups, such as incarcerated Black people, might significantly reduce healthcare costs, diagnostic burden, and needless patient follow-up. This study demonstrates the potential of precision hematology in reducing structural inequities and improving treatment in underserved regions.