I don't give blood routinely unfortunately, tho I know I ought to. Sometimes I can just tell when it's elevated, or at least I think I can tell. Once, when I felt it was high, I went to give blood and lo and behold I was just shy of the cut off.
I'd like to add a little bit of info to the discussion that I happened upon quite accidentally. My wife's dad ended up in the hospital due to, in short, cirrhosis of the liver. Almost died. My wife, who was very concerned, began researching things related to his condition, and while we were watching a YouTube video in the subject, the researcher briefly discussed how a poorly functioning liver can be a root cause of high blood pressure. Since the blood is filtered through the liver, if it is not functioning properly, the blood basically gets backed up in the liver thus causing high blood pressure. This notion gave me pause since many of our kind use compounds that are quite harsh on the liver, and it got me wondering just how much the use of such and the consequent damage caused may in fact contribute to high blood pressure in our "community." The researcher noted that many, if not most doctors giving treatments to patients with high blood pressure never consider treating the liver to ameliorate high blood pressure. He believes, like many of us do, that doctors rather sell more symptom relieving drugs than attack the cause, which is often less expensive and require little to no medication (think TRT for example). One change he mentioned, besides cutting alcohol, was reducing processed foods, and sugar. The liver has to do some serious acrobatics to deal with the large amounts if sugar most people consume. Anyhow, just something to chew on with respect to the issue of high blood pressure.