Free hemoglobin that passes into the urine may be absorbed by proximal renal tubular cells, where it is converted to cytoplasmic hemosiderin. Hemosiderin may enter into the urine as cells break down or are sloughed off.


Appearance of hemosiderin in centrifuged specimen on routine urinalysis:

(1) coarse brown granules in renal tubular epithelial cells

(2) coarse brown granules in cellular casts

(3) free coarse brown granules


Confirmation as hemosiderin: iron stain (granules blue on Prussian blue stain)


Occurrence of hemosiderinuria

(1) intravascular hemolysis

(2) paroxysmal nocturnal hemoglobinuria

(3) multiple transfusions (reflecting hemolytic anemia or delayed transfusion reactions)

(4) hemochromatosis (as part of the generalized iron deposition)

(5) myoglobinuria


The patient may or may not have a history of hemoglobinuria or passing red-colored urine.


Reasons the test may be requested:

(1) detect low grade hemoglobinuria

(2) confirm recent hemolytic episode

(3) presence of unexplained anemia

(4) confirm findings seen on examination of the urine sediment


To read more or access our algorithms and calculators, please log in or register.