Hematological malignancies are a group of diseases where several cancers are generated from blood-forming tissues/cells of the body. The cancer groups are highly heterogeneous, in that some diseases are biologically distinct in terms of protein expression, molecular progression, and biomarker characteristics, whereas other diseases are clinically variable in terms of treatments and prognostics. Recent improvements in neoplasm classifications have made significant in-roads towards a greater understanding of affected lineages, therefore hematological neoplasms can be divided into two primary categories; myeloid and lymphoid neoplasms, and each lineage can be further subdivided into several disease types. While the complexity of this disease group cannot be questioned, facilitating a rapid diagnosis and associated therapeutic intervention are key to reducing disease mortality and morbidity in patient groups. However, current diagnostic approaches for this disease group are equally complex and heterogeneous, therefore this comprehensive review aimed to catalog and appraise hematological characterization techniques to facilitate a greater understanding of disease classification, diagnosis, monitoring, and importantly, selection of appropriate therapies for hematological malignancies.