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: Social & Preventive Medicine
Sensitivity measures: 
Select and explain. 
A. True negative, B. True positive, C. False positive, D. False negative
B: True positive
Answer: B: True positive 
Explanation: Sensitivity measures true positive cases.
"The term sensitivity was introduced as a statistical index of diagnostic accuracy.
It has been defined as the ability of a test to identify correctly all those who have the disease, that is 'true positive'.”