Thiamine deficiency, the thiamine level is best monitored by

(Trans ketolase level in RBC) (377 - Lippencott's 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)