I was given 4 boxes of unopened Humalog by my diabetic nurse. It had belonged to another patient who had passed and the info had been black markered out and a sticker placed on the expiry date. I used the insulin and found that my sugars were high to often and was increasing the dose until I was up to 30-40 at some meals. In hind site I realize that is way to much insulin to take for my size, weight and eating habits. I had weight loss that I excused through alot of excercise thru my work. I was always tired which I also associated with long days of full on excercise. I can see now that is was the energy level I was keeping at high that helped me to coast along with high sugars and not send me into lows as it should have with the amount of insulin I was using. The Humalin I was using at night time was my own from my pharmacy and I even increased the dose of my night time because things were not right during the day. I did not have enough knowledge of the symtoms to question my abiltiy to manage my diabetes. Missing the signs put me into the situation of having a serious DKA attack. I have no idea how this insulin was stored or why a patient had four boxes at one time but it sits on my mind that the insulin I used was compromised in its travel and/or storage before coming to me and the issue of being 10 away from expiry when a usual 3 years is good before expiration date. Does insulin loose its strength during a period of possible incorrect storage. I have may questions but start with this one.