Eleash - I also wanted to chime in. I would definitely ask Dr M if he would recommend doing different or more extensive blood testing on you in addition to a biopsy. There are local blood tests and also bloodtests in Chicago that he recommends based on your medical history. Don't put yourself through a cycle until you have peace of mind that you have been tested for NK comprehensively. I am sure that Dr M won't ask you to do further tests unless your medical history warrants it. So that in itself would be peace of mind for you and you could go ahead with your next cycle without that additional worry.