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.
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, it will explain how to distinguish DANC from pathological neutropenia, and guide learners through its genetic basis and possible mechanisms. The program鈥痺ill also review the challenges that people with DANC may encounter and how to mitigate them. or access the individual resources below.
DANC Diagnosis: Printable Resources

Neutropenia Navigator: An Approach to Interpret Absolute Neutrophil Count (ANC)
It鈥檚 not always easy to tell when low Associated Neutrophil Count (ANC) is something to worry about. This handy practical guide to the hierarchy of concern for low ANC is great to print and keep in your practice. Download the Algorithm
A Guide to Duffy null-associated Neutrophil Count (DANC): Provider-Patient Consultation Tool
Duffy null-associated neutrophil count (DANC) is often not fully understood, leading to unnecessary medical tests and health inequalities. This consultation tool serves as a practice aid to helps patients learn more about DANC, the challenges it may present, and steps they can take to ensure their health needs are met. Share it to support your patients in navigating their healthcare journey. Download the Consultation ToolDANC Diagnosis: Interactive Learning
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
Additional Publications and Resources
- Duffy null genotype or Fy(a-b-) phenotype are more accurate than self-declared race for diagnosing benign ethnic neutropenia in Brazilian population
Presentations
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].