I went through tests for this years ago. Before i get too deep into it, my turned out to be secondary polycythaemia, caused by chronic dehydration. Basically, used to drink heavily, and never drank a drop of water. Then one day i found a small lump in my groin, and got sent off to hospital. The lump turned out to be a superficial blood clot. I was very lucky, that's where the clot decided to appear. Because it was superficial, no blood thinning treatment was required. But my red blood count was all over the place, and it was causing my blood to thicken as i simply had too much red blood cells.

Anyway, during the whole diagnosis process, i was freaking out. Google wasn't really a thing back then, and what little information i could find on the net all looked bad. But during one particularly bad appointment, the haematologist asked me "how would you react if you had been diagnosed with type 2 diabetes". I shrugged my shoulders and said I'd probably be ok with that rather than polycythaemia. She said the reality is, not many people really get ruffled with a type 2 diabetes diagnosis because it's so prevalent. But she said if i got diagnosed with polycythaemia, and someone in the next room got diagnosed with diabetes at the same time, at the same age, and all things were equal, I'd out live the diabetic patient easily. Those people who tend to struggle with polycythaemia tend to have coexisting morbidities or are at a very advanced age. Most people with the condition tend to die with polycythaemia, not from polycythaemia.