This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Screening, Subject name: Social & Preventive Medicine
Lead time is: 
Select and explain. 
A. Time from early diagnosis to starting treatment, B. Time from treatment to mortality, C. Time between detection of disease through screening and its clinical symptoms, D. Time between clinical symptom to complete treatment
C: Time between detection of disease through screening and its clinical symptoms
Answer: C: Time between detection of disease through screening and its clinical symptoms 
Explanation: Ans. (c) Time between detection of disease through screening and its clinical symptomsRef: K. Park 23rd ed. / 99-100* Lead time is the length of time between the detection of a disease and its usual clinical presentation and diagnosisOR* It is the time between early diagnosis with screening, and when diagnosis would have been made without screening.