Generally speaking, are blood pressure apps for the iPhone accurate?

Generally speaking, are blood pressure apps for the iPhone accurate?

No

Definitely not.

Just an app? Not likely. But a sphygmomanometer + app can be calibrated with a physician's sphygmomanometer and be pretty accurate. I use

The Health Mate app tracks blood pressure and heart rate, and works with a pedometer app to count steps.

NO look at the description of the app it will probbably say for use as a prank. Almost ALL are not real unless you buy an external device and it connects to your phone.
An example of one such device