At my doctor’s office, my systolic pressure is always in the 150’s. At home when I take it, it’s always in the 120’s. I brought my blood pressure machine to my doctor’s office once and checked it there. It measured the same as my doctor’s machine, so I know I’m getting accurate readings from both machines. There’s no way to explain it except that I always am a bit nervous seeing a doctor as I’m always afraid they’ll find something serious wrong with me that I wasn’t aware of.