TS is a diagnosis that doctors make after verifying that the patient has had both motor and vocal tics for at least 1 year. The existence of other neurological or psychiatric conditions can also help doctors arrive at a diagnosis. Common tics are not often misdiagnosed by knowledgeable clinicians. However, atypical symptoms or atypical presentations (for example, onset of symptoms in adulthood) may require specific specialty expertise for diagnosis. There are no blood, laboratory, or imaging tests needed for diagnosis. In rare cases, neuroimaging studies, such as magnetic resonance imaging (MRI) or computerized tomography (CT), electroencephalogram (EEG) studies, or certain blood tests may be used to rule out other conditions that might be confused with TS when the history or clinical examination is atypical.
