This is not as cut and dry as we would like. There is studies that say automatic is better and there are studies that say manual is better. But one things appears to be consistent as that the automatic readings appear to run up to 15 mmHg higher.
What causes the error could be due to operator error, improper patient positioning, patient anxiety, patient body position and body movement. The American Heart Association recommends Upper Arm Monitors. A physician we spoke to said, " it is important to stick with the same device and use the same way because what they are looking for is trends in the numbers."
When you see your Doctor you may see what they suggest for you to use