(P-TS-5) ABO and RhD Blood Group Frequencies in a Diverse, Statewide Patient Population

ABO and RhD blood group frequencies vary across populations, but published literature has historically reported them by racial group, which may not accurately reflect real-life, diverse populations with varied ancestries.

 
We sought to determine the distribution of ABO and RhD blood group frequencies among a large cohort of patients in California (CA) with the goals to characterize the population and assess its alignment with blood donors.

Study

Design/Methods: This retrospective, multi-center study examined patient blood types over a 5-year period (March 1, 2018 – February 28, 2023) at 5 academic medical centers across CA. Patient demographics and blood group frequencies were analyzed and compared to US and CA demographics as reported by the US Census Bureau, as well as to published blood group frequencies among US blood donors.

Results/Findings:

In aggregate, 467,745 patients underwent blood typing at the 5 centers. Compared to the US population, by self-report, CA patients included a higher proportion of Asian (12.3% vs. 5.9%) and Native Hawaiian or Pacific Islander (0.6% vs. 0.2%) individuals, and fewer Black or African American (7.4% vs. 12.2%) and White (52.8% vs. 60.9%) individuals, although analysis was limited by a subset of patients whose race was not reported or unknown (7.1%).

Among CA patients, blood groups O, A, B, and AB represented 46.2%, 35.8%, 14.1%, and 3.9% of the population, respectively.  The proportions of RhD-positive and RhD-negative patients were 90.0% and 10.0%, respectively (Fig A).

 
Compared to the US blood donor population,¹ CA patients had a smaller fraction of group A (35.8% vs. 37.1%) and a larger fraction of group B (14.1% vs. 12.2%) and RhD-positive (90.0% vs. 85.4%) individuals. A chi-square test demonstrated that, among CA patients, the distribution of ABO blood groups and the proportion of RhD-positive patients were significantly different than those of the reference US donor population [ABO: X² (3, N=467,745) =1567, p < 0.0001; RhD: X² (1, N=467,745) = 8235, p < 0.0001].

Conclusions: Among a large population of CA patients, the ABO and RhD blood group frequencies differed significantly from US blood donors; notably, group B patients represented 14.1% and RhD-positive patients 90.0% of the population. Accurate characterization of the distribution of ABO/Rh blood groups in a diverse patient population, rather than assumptions based on any single racial group, may aid in donor recruitment, inventory planning, and medical decision-making. The ABO and RhD frequencies in this population of CA patients reflects a potential misalignment between blood donors and recipients that could have significant consequences and warrants further investigation.

References:
1 Garratty G, Glynn SA, McEntire R, Retrovirus Epidemiology Donor Study.  ABO and Rh(D) phenotype frequencies of different racial/ethnic groups in the United States.  Transfusion 2004; 44(5): 703-706.