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: Unknown
[{'content': 'Which of the following tests is gold standard to diagnose a case of PHN? \nSelect and explain. \nA. HAMS test, B. Sucrose lysine test, C. Flow cytometry, D. Bone marrow', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ref. Robbins Pathology. 9th edition. Page. 642\n\nDiagnostic methods\n\n\nHAM test – no more used\nGel card test\nFlow cytometry – IOC\nBest – FLAER (Fluorescent Aerolysin test)', 'role': 'assistant'}]