<prompt> Which of the following is the best method for monitoring thiamine level in blood?G6PD activityReticulocytosisAbsolute thiamine level in bloodTransketolase level in blood  <response>: Thiamine deficiency is diagnosed by an increase in erythrocyte transketolase activity observed upon addition of thiamine pyrophosphate. The activation of apo-transketolase the enzyme protein in erythrocyte lysate by thiamine diphosphate added in vitro has become the accepted index of thiamine nutritional status. Ref: Harpers Illustrated Biochemistry, 26th Edition, Pages 488-489 ; Lippincott Biochemistry, 2nd Edition, Page 322 ; Textbook of Biochemistry By D M Vasudevan, 3rd Edition, Page 269 