This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Beta thalasemmia, Subject name: Pathology
Which of the following is best to confirm diagnosis of thalassemia trait in a lady with positive family history of thalassemia? 
Select and explain. 
A. Elevated HbA2, B. Reticulocytosis, C. NESTROFT, D. Peripheral smear
A: Elevated HbA2
Answer: A: Elevated HbA2 
Explanation: To Confirm diagnosis of Thalassemia trait, following can be seen HPLC of Hb Increased HbA2 levels (>3.5%) NESTROFT is useful in screening this disease.