The normal values used as a diagnostic tool and for comparison of cranes were established in the early 1970's. In that early study, no effort was made to look at factors such as age, sex, or subspecies. In addition, during the early study disease problems (primarily disseminated visceral coccidiosis) and nutritional problems were undiagnosed and uncontrolled. For 2 years during the annual health examinations of cranes at the USGS Patuxent Wildlife Research Center (Patuxent), we collected blood from healthy cranes for analysis. We found significant differences between the values reported from the 1970's and the values seen in this study for 8 blood parameters for Florida sandhill cranes (Grus canadensis pratensis), 6 blood parameters for greater sandhill cranes (G. c. tabida), and 6 blood parameters for whooping cranes (Grus americana). In addition, there were significant differences for some hematology and serum chemistry values based on the age of the cranes.