Routine blood tests are usually less informative although some specific blood tests like Lyme serology, celiac screening, Angiotensin-converting enzyme (ACE; for neurosarcoidosis), cholestanol and bile alcohol (cerebrotendinous xanthomatosis), anti-GAD antibodies (glutamatic acid decarboxylase; GAD encephalitis) and anti-thyroid peroxidase (TPO) antibodies (Hashimoto’s encephalopathy) can be helpful to identify the causes of SPT in the right clinical context [33, 40, 41, 55, 56, 68]. This evidence concerns the gene TPO and viral encephalitis.