POTS is diagnosed based on increased heart rate of more than 30 beats per minute in adults and more than 40 beats per minute in adolescents with no major drop in blood pressure from supine to standing or after tilt table from supine to 70 degrees upright.  Many patients have POTS as an isolate...

I agree with above. POTS can also be both under and over diagnosed, and objective findings are important to carefully measure and document - and use of tilt table is essential. A nice meta analysis can be found here: Reducing the Rate of Misdiagnosis of Postural Orthostatic Tachycardia Syndrome.Furt...