 Hemosiderophages are alveolar macrophages that have ingested and digested red blood cells from previous episodes of EIPH.The end product of the digestion of the red blood cells is an iron-storage complex known as hemosiderin.Bronchoalveolar lavage (BAL) is a procedure whereby a small volume of fluid is put into the airways in order sample the cells and fluids of the aveoli and epithelium of the bronchi.