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: Biochemistry
Thiamine level is best monitored by 
Select and explain. 
A. Transketolase level in blood, B. Thiamine level in blood, C. G6PD activity, D. Reticulocytosis
A: Transketolase level in blood
Answer: A: Transketolase level in blood 
Explanation: The activation of apo-transketolase in erythrocyte lysate by thiamine diphosphate added in vitro has become the accepted index of thiamine nutritional status.