The red blood cell distribution width (RDW) obtained with the hematological
automate MS9, was analysed in 1400 adult dogs. Comparing values obtained i
n healthy dogs and in diseased dogs, higher RDW values were observed in iro
n deficient anemia and in regenerative anemia. Lower values were observed i
n case of inflammation. Some high values of RDW were observed in non anemic
dogs and in dogs with non regenerative anemia. Some of them had porto syst
emic shunt or poodle macrocytosis.