Which of the following laboratory findings is characteristic of CML?

In chronic myeloid leukemia (CML), one of the hallmark laboratory findings is an increased number of basophils. This is significant because CML is characterized by the proliferation of myeloid cells in the bone marrow and peripheral blood, which results in an elevated white blood cell count, specifically with basophils and eosinophils often being markedly elevated. The increase in basophils can often be used as a distinguishing feature of CML compared to other myeloproliferative disorders.

The distinct presence of basophils is associated with the overarching pathophysiology of CML, where the Philadelphia chromosome and the BCR-ABL fusion gene play a critical role in the clonal expansion of these atypical cells, resulting in an abnormal increase of basophils over time. This finding can help to confirm a diagnosis of CML in conjunction with other clinical and laboratory assessments.