<prompt> Thiamine deficiency, the thiamine level is best monitored byTansketolase level in serumTransketolase level in RBCTrans aminase level in serumTrans aminase level in RBC  <response>: Trans ketolase level in RBC 377 - Lippencotts 3rd 167- 7th Thiamine deficiency is diagnosed by an increased in erythrocyte transketolase activity observed on addition of thiamine pyrophosphate The transketolase activity in erythrocytes is decreased Measurement of RBC transketolase activity is a reliable diagnostic test to assess thiamine deficiency. The increase in this enzyme activity more in severe deficiency by the addition of TPP is an index of the degree of thiamine deficiency LA PA ratio: Abnormal blood lactic acid Pyruvic acid is said to be more specific indicator of B1 deficiency 160-Rama shinde 6,h 