A healthcare provider must rule out potentially reversible causes of symptoms, like side effects from drugs, and other conditions, like hyperthyroidism or infection. A physical exam, medical history, or blood testing may all be included in their assessment.
A common procedure to diagnose POTS is a tilt table test, in which a person is strapped to a table that slowly moves them into an upright position. Blood pressure, heart rate, and heart rhythm are recorded, as well as any symptoms that occur during the procedure. In adults, an increase in heart rate of more than 30 bpm upon standing or during the tilt table test is used to define POTS; the increase may be larger in adolescents (more than 40 bpm).