blast

Meaning of blast: A blast is an immature precursor cell, most often found in the bone marrow, that has not yet developed into a mature blood cell type.

Definition of blast

A blast is an immature cell, most commonly used to describe an early-stage blood cell found in the bone marrow before it has matured into a specific type such as a red blood cell, white blood cell, or platelet. Small numbers of blasts are normally present in the bone marrow as part of ongoing blood cell production.

The word is also used as a suffix in terms such as myeloblast, lymphoblast, and fibroblast to name immature or precursor cells of a particular lineage. In laboratory and pathology reports, the proportion of blasts among all marrow or blood cells is an important finding, since a substantially increased blast percentage can indicate a disorder of blood cell production.

The clinical significance of a blast count depends on the specific value, the type of blast identified, and the broader laboratory and clinical picture.