A Hierarchical Ensemble Inference Pipeline for Robust White Blood Cell Classification Under Domain Shifts
For clinical WBC classification, this method addresses domain shift robustness but yields only incremental gains (top ten ranking).
The authors propose a memory-augmented hierarchical ensemble pipeline for white blood cell classification that uses a feature bank and DinoBloom backbone with LoRA fine-tuning, achieving top-ten macro F1-score on the WBCBench dataset under domain shifts.
Automated white blood cell (WBC) classification is essential for scalable leukaemia screening. However, real-world deployment is challenged by domain shifts caused by staining protocols, scanner characteristics, and inter-laboratory variability, which often degrade model performance. The White Blood Cell Classification Challenge (WBCBench) at ISBI 2026 aims to advance robust WBC recognition, with a focus on accurately identifying blast cells and other clinically critical rare subtypes. We propose a memory-augmented, hierarchical ensemble pipeline for WBC classification under domain shifts, leveraging a feature bank and a DinoBloom backbone fine-tuned with LoRA. Our three-stage inference hierarchy combines k-nearest neighbors (kNN) retrieval at each level, reducing over-reliance on any single decision. Evaluated on the WBCBench dataset, our method ranks within the top ten by macro F1-score in the final testing phase.