This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Diagnosis of Pregnancy, Subject name: Gynaecology & Obstetrics
[{'content': 'Most sensitive test for measuring ss HCG levels for diagnosis of pregnancy is? \nSelect and explain. \nA. Serum beta HCG by ELISA, B. Urine pregnancy test, C. Immuno Radiometric assay, D. Radio immuno Assay', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Sensitivity of various tests for detection of Hcg Urine pregnancy test: + in 60-70% (sensitive to 150 mIU ) Serum beta hcg by ELISA: + in > 95% (sensitive to 5 mIU) Radio immuno assay: + in 100 % (sensitive to 1-2 mIU) can detect pregnancy on 7th day of ovulation Immuno Radiometric Assay: + in 100 % (sensitive to 0.5 mIU) can detect pregnancy on 7th to 10th day of ovulation', 'role': 'assistant'}]