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.

Duffy Status Assessment

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Duff Recommendations Infographic

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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 Diagnosis: 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 Algorithm

Redefining 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 Infographic

Duffy Testing to Benefit Children’s Population Health: A Cost-Effectiveness Analysis Infographic

Discover how Duffy testing in infancy can be cost-effective across the US under four common neutropenia work-up scenarios. Download the infographic to learn more.

Download the Consultation Tool

DANC Diagnosis: Interactive Learning

Understanding Duffy Status and Neutrophil Count: An Interactive Approach eModule

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

Absolute Neutrophil Count (ANC) Shuffle Mini Game

Six patients, all with a low ANC … can you solve the puzzle and send each patient to the right referral? Try our ANC "Guess Who" game and explore our other educational content on Duffy-null associated neutrophil count.

Play the Mini Game

Responding to Low Absolute Neutrophil Count (ANC): A Case Series

How can you tell when a low ANC is an emergency or something to be investigated later? Test yourself with our series of mini-cases and find out.

Take the Mini-Case Assessments

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.

DANC 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.

View eModule

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.

Play Mini Game

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 over testing and healthcare disparities in the real world, 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.

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Additional Resources

Key Publications

Additional Publications and Resources

Terms and Definitions

Questions

If you have questions or require additional information regarding DANC or the ANC by Duffy Status project, please contact treatingfairly@hematology.org.

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