ASH sets blood count reference ranges for Duffy-null people

The American Society of Hematology (ASH) has published reference ranges for white blood cell and neutrophil counts in children and adults with Duffy-null status, news-medical.net reports. The ranges appeared in Blood Advances and are described as the first of their kind. Duffy-null status is a common genetic trait associated with naturally lower circulating white blood cell counts; according to ASH, it affects more than 66% of people with African or Mediterranean ancestry in the US. news-medical.net

Researchers at 23 U.S. sites collected 1,412 samples from Duffy-null individuals. The samples were used to validate adult ranges and to collect the first data for pediatric ranges. The authors reported no meaningful differences in the ranges across sites once differences in collection strategies and patient populations were accounted for. news-medical.net

Why standard ranges can mislead

The Duffy antigen is a protein on red blood cells; in Duffy-null individuals it is naturally absent. Its absence protects against infection with malaria parasites. It also affects the distribution of neutrophils: more of them are concentrated in tissues and fewer circulate in the blood, from which samples for laboratory tests are drawn. news-medical.net

As a result, total white blood cell and neutrophil counts in Duffy-null people are lower than in Duffy-positive people. Under standard ranges this can be flagged as neutropenia, which may lead to bone marrow biopsies, exclusion from clinical trials or discontinuation of therapies such as chemotherapy. ASH stresses that Duffy-null status is not a disease but a genetic variant. news-medical.net

The new ranges

The values are given for absolute neutrophil count (ANC) and white blood cell count (WBC), in ×10⁹/L. Adults: ANC 1.03–7.30, WBC 3.0–10.7. Children 6 months to 2 years: ANC 0.53–4.50, WBC 4.4–12.6. Children 3 to 6 years: ANC 0.78–4.67, WBC 3.8–10.8. news-medical.net

Children 7 to 12 years: ANC 0.87–5.34, WBC 2.9–10.1. Children 13 to 17 years: ANC 0.90–4.89, WBC 3.1–9.2. Reference intervals for children under 6 months old still require further research. news-medical.net

Study author Maureen Achebe of Brigham and Women's Hospital and Dana-Farber Cancer Institute said the ranges are a concrete, implementable step toward recognizing what is normal for Duffy-null individuals. The work is part of ASH's ANC by Duffy Status Project. As part of the same initiative, ASH also published a study in Blood Advances reporting that universal pediatric testing for the Duffy-null variant is cost effective. news-medical.net

ASH publishes first reference ranges of white blood cell counts for Duffy-null children and adults

Why standard ranges can mislead

The new ranges

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