Figure 2. Diagnostic workflow of patients with suspected MPN and low JAK2^V617F allele burden.

*Main hematological abnormality motivating the JAK2^V617F evaluation. ‘’Histology-based’’ diagnosis was made when BM histology was available. In patients that were unable or refused to perform BM evaluation, prospective clinical observation and prospective molecular monitoring were crucial to direct diagnostic uncertainty, allowing to define a ‘’Clinical based’’ or ‘’Molecular based’’ diagnosis, respectively.