Pete,
While not an issue for me, I did some reading on CEA values. Every time something new (to me) about BC shows up here, I want to know something about it.
I found only one article with some research including high values.
The following study may be of interest to your doc, or at least offer a look at a wide range of CEA values. As would be expected for most tests, this article finds no absolute number at which the result is always positive. This study was looking a colorectal cancer and CEA value, Healthy controls are listed with CEA values approaching 100.
www.ncbi.nlm.nih.gov/pubmed/29968766
Validation of Assaying Carcinoembryonic Antigen in Human Serum by Using Immunomagnetic Reduction.
Sci Rep. 2018 Jul 3;8(1):10002. doi: 10.1038/s41598-018-28215-1.
I hope this may be of interest. I see no other responses to your question.
Best,
Jack