Tilt test--from the necessary to the indispensable.

The head-up tilt test (HUTT) is widely used for investigation of syncope and presyncope, since it allows diagnosing different types of dysautonomia. The main cause of syncope is the vasovagal syndrome, the most common diagnosis among patients with HUTT indication. The test has been used for nearly 20 years, but many doctors are unaware of the methodology. After the cardiac causes of syncope are ruled out, the appropriate indication of the test and instructions to patients are important to ensure that the test will be carried out in a safe and relaxed manner. There are controversies in the literature over the diagnostic capacity and reliability of results. Studies with various protocols may explain the variability of results. This review describes the guidelines-recommended methodology and indications, complications, limitations and perspectives of this test.