Proficiency testing of reticulocyte counting in Ontario.

The reticulocyte count reflects the erythropoietic activity of the bone marrow and is thus useful in both the approach to the diagnosis of anemia and in monitoring bone marrow response to therapy. Traditionally, reticulocyte quantitation relied upon microscopic techniques; recently automated reticulocyte quantitation has become widely available. External quality assessment (EQA) of reticulocyte quantitation has not been widely reported; this paper presents data from reticulocyte EQA surveys conducted in Ontario between November 2000 and October 2004.