Only in one dog with FRD negative for fecal blood test, low serum iron (45 μg/dL, reference range 81–220 μg/dL), low transferrin saturation percentage (17.5%, reference range 25–52%), and concurrent mild normocytic anemia (Hct 32%, MCV 62 fL) were found. Here, TF is linked to anemia (phenotype).