CEA test: Carcinoembryonic antigen test is to detect response to therapy in cancer patients, especially colon cancer, with normal range of less than 2.5 (less than 5 in heavy smokers). Note that a positive test may not always be indicative of cancer.
Os Trigonum Syndrome. An Os Trigonum is a small, extra bone found at the back of the ankle in approximately 5-10% of people. Often it goes completely unnoticed, not causing any problems.
Some people, for one reason or another, have a small extra bone in their feet that ends up causing them trouble, too. It is called an os trigonum, and it sits in the gap behind the ankle bone (talus) and above the heel bone (calcaneus).