Hemosiderin-laden macrophages in bronchoalveolar fluid 2020-04-28T07:20:09Z Hemosiderin, a product of hemoglobin degradation, appears at least 48-72 hours after bleeding and is helpful in distinguishing diffuse alveolar hemorrhage from surgical trauma. Mild interstitial thickening, organizing pneumonia, or diffuse alveolar damage can also be seen. Siderophages in bronchoalveolar fluid Hemosiderin-laden macrophages (HLM) in bronchoalveolar lavage (BAL) fluid were originally known as adiagnostic biomarker of alveolar hemorrhage, but have also been observed in idiopathic pulmonary fibrosis (IPF) with histopathological pattern of usual interstitial pneumonia (UIP). Accumulation of hemosiderin laden alveolar macrophages Abnormal alveolar macrophage morphology