reticulocyte count is a very good friend in evaluating anaemias

An example of metaphor in a science text:

"The pathophysiologic classification of anemia after transplantation is similar to that of nontransplanted patients. The major categories of decreased production, increased destruction, maturation defects, and bleeding apply, although the universe of differential diagnoses is much smaller, since most of the congenital and acquired hematopoietic defects that might be present in the donor will have been avoided. The RBC indices can be helpful, although a mild to moderate macrocytosis is common for months or years after transplantation and is not necessarily indicative of nutritional deficiency, abnormal DNA synthesis, or reticulocytosis. The reticulocyte count is a very good friend in evaluating anemias, and this applies in transplantation as well."

Antin, J. H. (2018) Secondary Anemias Associated with Hematopoietic Stem Cell Transplantation, in Edward J. Benz, Nancy Berliner, & Fred J. Schiffman, Anemia. Pathophysiology, Diagnosis, and Management, Cambridge University Press, 179-184.