Establishing Reference Intervals for White Blood Cell and Absolute Neutrophil Counts in Duffy Null Individuals

Area of Science:

• Hematology
• Immunogenetics
• Population Health

Background:

• The Duffy (Fy) blood group system, governed by the ACKR1 gene, is crucial in transfusion medicine and malaria susceptibility.
• Duffy-null phenotype (Fy(a-b-)) is linked to reduced baseline white blood cell (WBC) and absolute neutrophil count (ANC).

Purpose of the Study:

• To establish specific reference intervals for WBC and ANC in Duffy-null individuals.
• To enhance diagnostic accuracy and minimize unnecessary clinical interventions for this population.

Main Methods:

• Retrospective analysis of 1695 adult patients undergoing complete blood count and red blood cell phenotyping.
• Inclusion of 122 healthy Duffy-null individuals.
• Establishment of 95% reference intervals using nonparametric methods per CLSI guidelines.

Main Results:

• Median WBC and ANC in Duffy-null cohort were significantly lower than institutional medians (3.24 vs. 6.65 × 10³ /µL and 1.45 vs. 4.45 × 10³ /µL, respectively; p < 0.01).
• Derived 95% reference intervals (WBC: 2.43–7.05 × 10³ /µL; ANC: 1.01–4.34 × 10³ /µL) fell below conventional thresholds.
• Lower ANC bound was below the standard neutropenia cutoff.

Conclusions:

• Findings underscore the necessity for Duffy-null-specific hematologic reference ranges.
• Adopting these intervals can reduce misclassification and unnecessary diagnostic procedures.
• Promotes personalized clinical care for individuals with the Duffy-null phenotype.