My first CEA test was done in Thailand, and it was 4.56.
The second one, done at Seattle Care Cancer Alliance, two months later was 5.8
The third one done by Quest was 2.8 in December 2016.
The fourth one at SCCA was 5.9. June 2017
This month, back at Quest labs, it was 2.9. March 2017.
Are the different scales depending on the labs? I imagine if I tested at SCCA, I would test 5 something, not 2 something.