Bone marrow aspirates from two dogs were stained with Prussian blue, which detects iron in hemosiderin (causing a blue or black stain reaction, depending on the amount of iron).
A:Spicules from an iron deficient dog (due to chronic gastrointestinal hemorrhage) are negative for Prussian blue, indicating a complete absence of iron. It takes a long time to get to this stage in an adult animal because there are normal stores of iron. Less time is required for a young animal as they usually have low iron stores to begin with.
B:Variably sized chunks of blue to black are seen in the bone marrow spicules from this normal dog. This would be judged as “adequate” iron stores (meaning plenty is available for hemoglobin production and erythropoiesis). Note, that even though the iron looks like it is outside cells, all the iron is within macrophages in the bone marrow stroma.
