This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: miscellaneous, Subject name: Pathology
[{'content': 'Donath landsteiner test is used in diagnosis of ?- \nSelect and explain. \nA. Paroxysmal nocturnal hemoglobinuria, B. Paroxysmal cold hemoglobinuria, C. March hemoglobinuria, D. Favism', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Paroxysmal cold haemoglobinuria (PCH). In PCH, cold antibody is an IgG antibody (Donath-Landsteiner antibody) which is directed against P blood group antigen and brings about complement-mediated haemolysis. Attacks of PCH are precipitated by exposure to cold. PCH is uncommon and may be seen in association with teiary syphilis or as a complication of ceain infections such as Mycoplasma pneumonia, flu, measles and mumps HARSH MOHAN Text book of pathology 6th edition pg no 313', 'role': 'assistant'}]