Calmodulin level in whole blood correlates with the percentage of reticulocytes

We studied the calmodulin-like activity (CaM) level in hemolyzed samples of whole blood after determining the percentage and absolute number of reticulocytes present. Twenty-six samples from 25 people with a range of reticulocyte counts were studied. CaM levels correlated with the percentage (r = 0.63, P less than .01) and absolute number (r = 0.64, P less than .01) of reticulocytes present, indicating that the calmodulin-like activity level in whole blood was inversely related to erythrocyte age.