My mum had a check up last week which involved a blood test . Her CEA level was a little high at 12 so we went back and did another one which later came back at 16. We are going to have all the checks ups necessary to see if there is cancer anywhere but as she is a smoker with Rheumatoid arthritis im wondering if this can cause a high level of 16, should we be worried ?

Summarized question: CEA level high, smoker, rheumatoid arthritis. Cancer?