This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
Perl's stain or prussion blue test is for: 
Select and explain. 
A. Bilirubin, B. Calcium, C. Hemosiderin, D. Glycogen
C: Hemosiderin
Answer: C: Hemosiderin 
Explanation: Perls' stain (Prussian-Blue Reaction) is to demonstrate Ferric salts in tissues. These are seen as iron  granules in bone marrow macrophages, erythroblasts (Sideroblasts) and erythrocytes (Siderocytes) in  blood ﬁlms and haemosiderin in spun urine.