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: Gynaecology & Obstetrics
Minimum level of HCG detected by radio immunoassay is : 
Select and explain. 
A. 1.5-3.5 IU/m1, B. 0.5-1 IU/m1, C. 0.02-0.05 1U/m1, D. 0.001 IU/m1
D: 0.001 IU/m1
Answer: D: 0.001 IU/m1 
Explanation: Ans. is d i.e. 0.001 1U/m1 Pregnancy tests All the pregnancy tests used now days are immunological, which function on the principle of detecting HCG quantitatively or qualitatively, either in the urine or blood :