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Summary: ABO‐non‐identical (ABO‐ni) platelets may be another risk factor for immune platelet transfusion refractoriness (i‐PTR). We examined the effect of such platelets on i‐PTR and subsequent platelet support through retrospective analysis of 17 322 New Zealand patients receiving ≥1 platelets. Immune PTR was defined as PTR with anti‐HLA‐I/HPA positivity. Univariate and multivariate analyses determined the independent risk factors for i‐PTR. One hundred and eighty‐eight patients (1.1%) had i‐PTR and received more ABO‐ni platelets than non‐refractory patients (53.2% vs. 29.5%; p < 0.001). More non‐O than group O patients had received ABO‐ni platelets before i‐PTR diagnosis (67.6% vs. 32.5%; p < 0.001). Female sex (p < 0.001), age ≤ 60 years (p = 0.004), haematology patients (p < 0.001) and ≥2 ABO‐ni platelets (p < 0.001) were the independent risk factors for i‐PTR. More i‐PTR patients with anti‐HLA‐I were non‐O compared to group O (90.1% vs. 75.3%; p = 0.007). More with anti‐HLA‐I + anti‐HPA were group O than non‐O (24.7% vs. 9.0%; p = 0.003). ABO‐ni platelet‐exposed i‐PTR patients required matched platelets for longer than those receiving only ABO‐i platelets (96.5 vs. 59.0 days; p = 0.02). ABO‐ni platelets may be a risk factor for i‐PTR with dose effect. ABO‐i platelets should be considered whenever possible for at‐risk patients. [ABSTRACT FROM AUTHOR] more...