We have had a run of highs.... insulin was replaced only a couple of weeks ago.... in date.... have had issues since we received this batchof both Lantus and Apidra.... D has not been playing fair at all!! I have a vague recollection of reading years ago... that if the little rubber circle thing is 'bulging' and not flat that it indicated that the insulin has been compromised either by heat or had been frozen. Can anyone verify that this is the case? Have just checked both boxes of Lantus and Apidra and every single pen... has the 'bulging' rubber circle. My brain function is sadly lacking... due to lack of sleep... did I imagine this tidbit of information?? Surely not! Thanks for any thoughts on this.