When i take my blood pressure at home with my wrist monitor, arm laying flat on a table my bp reading is high. when i do it with elbow on table and hand slightly elevated at heart level it's a normal reading. which one is the right one?

Good observation. Always put the tips of fingers on arm u have BP monitor on. This normally puts the cuff at heart level to avoid hydrostatic errors. Fir every inch the cuff is below heart level the pressure will increase by 2 mm Hg. For every in. above heart level BP =+2 mm Hg. You can do this study yourself by checking pressure with wrist at various levels. So check BP until u r at zero point.

The correct way to measure blood pressure is to place hand at heart level. Other tips to correct measurement include: avoiding food/drinks/exercise 30 mins before, emptying the bladder, placing both feet on ground, and finding an appropriate sized cuff.