This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Haematology, Subject name: Anatomy
Which of the following is associated with highest risk of anaphylaxis 
Select and explain. 
A. Iron dextran, B. Iron sucrose, C. Ferumoxytol, D. Iron gluconate
A: Iron dextran
Answer: A: Iron dextran 
Explanation: Ref Harrison 19 th ed pg 629 intravenous iron dextran, anaphylaxis is a con- cern. Anaphylaxis is much rarer with the newer preparations. The factors that have correlated with an anaphylactic-like reaction include a history of multiple allergies or a prior allergic reaction to dextran (in the case of iron dextran)