New Blood Ranges Fix False Low Counts in Duffy-Null

If you have African or Mediterranean ancestry, your normal neutrophil count may now be read against ranges built for your trait.

Updated on Nov. 5, 2026 in Allergies

Photograph of a wooden rack holding a row of clear, empty glass test tubes on a pale laboratory bench under cool daylight. — The American Society of Hematology published the first blood reference ranges for people with the inherited Duffy-null trait, common among those of African or Mediterranean ancestry. AI Illustration. Upload story photo >

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The American Society of Hematology has established the first blood reference ranges designed for people who are Duffy-null, a common inherited blood trait. The ranges were published in Blood Advances and are intended to keep people with the trait from being wrongly flagged for low neutrophil counts. For readers with African or Mediterranean ancestry, who are most likely to carry the trait, the change addresses a longstanding measurement problem.

Why it matters

Under standard reference ranges, people who are Duffy-null may be mistakenly identified as having neutropenia, which can lead to unnecessary testing and worry. Because the trait affects more than 66% of people with African or Mediterranean ancestry in the US, the mismatch has reached a large population, and the new ranges give clinicians a more accurate baseline.

Researchers at 23 US sites collected 1,412 samples from Duffy-null individuals to validate adult ranges and generate the first pediatric data for four age categories. Despite differences in collection strategies and patient populations across sites, no meaningful differences in reference ranges were found after accounting for those factors.

The players

American Society of Hematology (ASH)

ASH is a professional medical society focused on blood disorders, including research, clinical guidelines and education for hematologists.

Blood Advances

Blood Advances is a peer-reviewed journal published by the American Society of Hematology, covering hematology research.

The details

Duffy-null status means a person lacks the Duffy antigen on red blood cells, a trait tied to ancestry and detected with a simple blood test. Duffy-null individuals tend to have more neutrophils concentrated in body tissues and fewer circulating in the blood, where routine blood draws measure them. Standard reference ranges do not account for this distribution, so a normal count in these individuals can look low on a report.

November 5, 2026: ASH announced the reference ranges and they were published in Blood Advances.

Health Landscape

Reference intervals are the benchmarks clinicians use to decide whether a lab result is normal, and most were built on populations that did not include carriers of the Duffy-null trait. This update offers the first ranges designed for that group, reflecting a broader push to make standard lab interpretation accurate across ancestry.

If you have African or Mediterranean ancestry and have ever been told your neutrophil count is low, it is worth asking your doctor whether Duffy-null status was considered in interpreting the result. Clinicians can use these ranges to avoid unnecessary follow-up when a lab value falls within the newly established norms for Duffy-null individuals.

The takeaway

A low neutrophil count is not always a sign of illness, especially in people who are Duffy-null. If a blood test flags neutropenia and you carry this trait or have relevant ancestry, discuss the result with your physician so it can be read against the appropriate reference range.