What are the reasons for there not being a blood pressure reading?

It is possible that you have an extra layer of fat, muscle, or other types of tissue above your artery.

Thus, the pressure within the artery may be less readable to the machine.

Trust me, if you had no blood pressure, you couldn't draw blood, and you would be dead right now.

If the instruments are fine, then it's either the nurse who did it wrong, or you have an interesting (probably harmless) genetic difference.

I've been getting the flu shot for several years. It's offered free to all Ontarians. They try to reduce the number of people in the emergency department in the winter. I've been getting it because I work in a drugstore and my mother was on immuno-suppressant drugs. She couldn't afford to get sick. She also had high blood pressure. They aren't many drugs available for people with high blood pressure. The ingredients in a lot of the cough/cold remedies will raise blood pressure. For most people it is acceptable but not for those with high blood pressure. So, I think they are just trying to look out for you. They want to make sure you don't get the flu and have to go through the "joys" of the flu. The few medications available don't always work for everyone. My mother never found them to really help. And when you use the stuff you aren't supposed to, it can be a really trip. My mother did that because she didn't know that she couldn't take just anything and thought she was having a heart attack. So, I plan to continue to get the flu shot. I find it really does help. Hope this helps. ♥D