Duffy-null Associated Neutrophil Count (DANC)
The Duffy blood group system is one of many that are used to classify blood types. People with the Duffy-null blood type often have a lower absolute neutrophil count (ANC) than most other people. This is called Duffy-null associated neutrophil count (DANC).
Individuals with the Duffy-null phenotype have no increased risk of infection but are often incorrectly labeled as having neutropenia. This can result in unnecessary, expensive, and invasive testing, delayed or discontinued chemotherapy or other critical medications, exclusion from clinical trials, and other negative consequences.
Through a multifaceted approach, ASH aims to improve the quality of care for individuals with DANC.
Clinical Recommendations
Many individuals with the Duffy null variant have lower absolute neutrophil counts (ANC) at baseline without increased infection risk. This may have significant implications for trial eligibility, medication dosing, and even health outcomes in clinical trials. ASH strongly recommends integrating Duffy testing into all relevant clinical trials to generate data to ensure optimal eligibility criteria and dose-modification criteria, assess outcomes by Duffy status, and allow for personalized patient care. This section outlines key considerations and emerging recommendations for integrating Duffy status assessment into clinical research.
Educational Resources
This educational program aims to improve awareness and understanding of Duffy-null associated neutrophil count (DANC), a common and under-recognized source of health inequality worldwide. Through patient case studies, the program will explain how to distinguish DANC from pathological neutropenia and guide learners through its genetic basis and possible mechanisms. The program will also review the challenges that people with DANC may encounter and how to mitigate them. View the full course on ASH Academy or access the individual resources below.
DANC Printable Resources
Pediatric Neutropenia Navigator: An Approach to Interpret Absolute Neutrophil Count (ANC) Algorithm
When is low Associated Neutrophil Count (ANC) something to worry about? This updated practical guide to the hierarchy of concern for low ANC, now including recommendations for children, is great to print and keep in your practice. Download the AlgorithmRedefining Normal: ANC and WBC Reference Intervals for Duffy Null Individuals Infographic
Discover how newly validated Duffy null-specific absolute neutrophil count (ANC) and white blood cell (WBC) reference intervals vary across age groups in adults and children. Download the infographic to keep these values on hand Download the InfographicDANC Diagnosis, Mechanisms and Epidemiology: Interactive Learning
Understanding DANC
What connects the Duffy blood group to widespread health inequalities? In the first of an upcoming three-module course, test your diagnostic skills with six case studies, learn more about Duffy-null associated neutrophil count and what it means for your patients. Go to the eModule
Mechanisms and Epidemiology of Duffy-null Associated Neutrophil Count (DANC) eModule
What lies behind Duffy-null associated neutrophil count (DANC) and how can we discuss it with our patients? Follow a conversation with a patient to review our knowledge of the epidemiology and biological basis of DANC, and how it affects healthcare in this interactive e-module. Go to the eModuleDANC Reference Intervals: Interactive Learning
Multicenter Study of ANC and WBC is Duffy null Individuals
How do validated Duffy null-specific absolute nutrophil count (ANC) and white blood cell (WBC) reference intervals vary across age groups? Follow along with a journal club discussion to review the validated Duffy null-specific ANC and WBC reference intervals for adults and children and explore how applying them can shape clinical decision-making in this interactive e-module.Module Coming Soon
DANC Reference Range Recall
Do you know your Duffy-null specific absolute neutrophil count (ANC) and white blood cell (WBC) reference intervals? Test your knowledge with this interactive flip-card memory game and learn the reference intervals that differ from standard institutional ranges.Module Coming Soon
DANC Expert Videos
Understanding Duffy-null Associated Neutrophil Count (DANC): Insights with Dr. Lauren Merz
How are blood groups, neutrophil counts, and health inequalities connected? Listen to Dr Lauren Merz explain some eye-catching research showing that people with certain ancestries are at risk of having vital medications stopped inappropriately, and why this happens.
Duffy Null-Associated Neutrophil Count: The Patient Perspective
Dr Rahma Warsam is a hematologist and also has Duffy null-associated neutrophil count (DANC). Listen as she describes how DANC leads to overtesting and healthcare disparities in the real worl, and how it impacts families.
Duffy null and Children
What connects the Duffy blood group to health disparities and overtesting in children? Dr Abraham Haimed explains how Duffy null-associated neutrophil count (DANC) manifests in children, and what you should remember as a clinician.
Absolute Neutrophil Count (ANC) by Duffy Status Project
ASH is at the forefront of addressing a critical health equity concern through its groundbreaking initiative - the Reconsideration of Absolute neutrophil count (ANC) Reference Ranges by Duffy Status. The initiative is funded by a grant from the Doris Duke Foundation and seeks to ensure that all individuals, especially those with Duffy-null associated neutrophil count (DANC), receive optimal care by redefining ANC reference ranges based on Duffy status.
Absolute Neutrophil Count by Duffy Status Among Healthy Black and African American Adults
Approximately two of three people identifying as Black in the U.S. are expected to have the Duffy-null phenotype. Of note, race and ethnicity are not biological facts but sociopolitical constructs. Genetic traits do not obey racial boundaries or geographic constructs, so using them as proxies requires extreme caution. While the Duffy-null phenotype is not exclusive to African or Arabian Peninsula genetic ancestry, it is most commonly found among these populations.
Additional Resources
Key Publications
- When non-Whiteness Becomes a Condition
- Absolute Neutrophil Count by Duffy Status Among Healthy Black and African American Adults
- Race, Genotype, and Azathioprine Discontinuation: A Cohort Study
- Development of Duffy Null–Specific Absolute Neutrophil Count Reference Ranges
- The Duffy Null Phenotype — Addressing a Source of Discrimination in Cancer Care
Additional Publications and Resources
- 2022 ASCP Choosing Wisely Recommendation includes Duffy-null testing
- Invisible Infrastructure in Haematology: Neutrophil Reference Ranges and the Duffy-null Phenotype
- The Duffy-null genotype and risk of infection
- Duffy null genotype or Fy(a-b-) phenotype are more accurate than self-declared race for diagnosing benign ethnic neutropenia in Brazilian population
- Ethnic neutropenia and treatment delay in African American women undergoing chemotherapy for early-stage breast cancer
- Neutrophil Counts in Healthy South African Infants: Implications for Enrollment and Adverse Event Grading in Clinical Trials in an African Setting
- The DARC Side of Inflamm-Aging: Duffy Antigen Receptor for Chemokines (DARC/ACKR1) as a Potential Biomarker of Aging, Immunosenescence, and Breast Oncogenesis among High-Risk Subpopulations
- Atypical chemokine receptor 1 on nucleated erythroid cells regulates hematopoiesis: https://pubmed.ncbi.nlm.nih.gov/28553950/
- The American Society for Clinical Pathology Expands List of Commonly Used Tests Physicians and Patients Should Question in Collaboration with ASCLS and ASM
Terms and Definitions
Questions
If you have questions or require additional information regarding DANC or the ANC by Duffy Status project, please contact [email protected].