What investigations are recommended to confirm thiamine deficiency in a patient with neurological symptoms?

Recommended investigations to confirm thiamine deficiency in a patient presenting with neurological symptoms:

There are no specific blood tests routinely recommended in UK guidelines to confirm thiamine deficiency in clinical practice. Instead, the diagnosis of thiamine deficiency, particularly in the context of neurological symptoms such as suspected Wernicke's encephalopathy, is primarily clinical.

Because of the urgency and potential severity of thiamine deficiency-related neurological complications, NICE guidelines recommend offering parenteral thiamine treatment immediately if Wernicke's encephalopathy is suspected, without waiting for confirmatory tests. This is due to the high risk of morbidity and mortality if treatment is delayed.

Laboratory confirmation of thiamine deficiency is not routinely required before treatment initiation, and no specific diagnostic blood tests are detailed in the provided NICE guidelines for confirming thiamine deficiency in neurological presentations.