I just found out that I have a kidney that is working only10%. I am 47 years old and this may be from since i was an infant. I only found out about this because I was having SEVERE pains on my left side kidney area. I had a CT done and will be going for further tests this week. After having blood work done, I was told that my calcium was at Critical Value. What exactly does that mean and what can be done to rectify that? Thank you.