A couple of other CBC pearls in a patient with anemia: 1. A high MCHC> 36 indicates they have a warm antibody (ie Coombs positive) hemolytic anemia or hereditary spherocytosis. 2. A MCV/RBC count 12 indicates thalassemia (eg MCV=62 and RBC count 6 million cells gives ratio 10.3 is 12 and most likely thalassemia). 3. A MCV/RBC count > 20 indicates iron deficiency anemia.