This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Screening for Disease, Subject name: Social & Preventive Medicine
Lead time is defined is- 
Select and explain. 
A. Time between diagnosis and treatment, B. Time between point where the diagnosis is made by screening test to usual diagnosis., C. Time between disease onset and outcome, D. Time between usual time of diagnosis and outcome
B: Time between point where the diagnosis is made by screening test to usual diagnosis.
Answer: B: Time between point where the diagnosis is made by screening test to usual diagnosis. 
Explanation: Ans. is 'b' i.e., Time between point where the diagnosis is made by screening test to usual diagnosis * The lead time is the time period between diagnosis by early detection (i.e., earliest point of diagnosis by screening test) and diagnosis by standard diagnostic tests. Lead time is the advantage gained by screening.