This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Tumor Markers, Subject name: Gynaecology & Obstetrics
CA 125 upper limit of normal is - 
Select and explain. 
A. 25U/ml, B. 30U/ml, C. 35 U/ml, D. 40U/ml
C: 35 U/ml
Answer: C: 35 U/ml 
Explanation: Ans. is 'c' i.e., 35 U/ml o Serum value of 35 U/ml of CA 125 repreents 1 % of the healthy females and is often accepted as the upper limit of normal in clinical practice.