Re: Right arm vs. Left arm.
it's normal for arms to have different readings due to the slightly normal irregular shape of the heart and arteries. A difference up to 20mmHG for the top number and 10mmHG for the lower number is fine. If the difference is greater then that, there could be a underlying problem.
It is recommended to use the arm that has the higher readings to take your BP. But seems like everyone, even DR's, get in the habit of always using left arm for some reason.
A lot of people have white collar syndrome and that's like taking your BP while driving a car in a traffic jam. If you check your BP regularly at home, and it's in normal ranges at home, then the DR's office is out of norm reading, it's because of being very anxious. If you go back home, relax, and daily BP is ok again, you're fine!