When I was 40, I had a moderately high CEA, so my GP sent me off to the Gastro guy for a colonoscopy. Found a couple cecal adenomatous polyps (so, wouldn't have been found by a sigmoidoscopy). Polyps were removed, so all is well (and they made me get colonoscopies every two years for a while).

I wouldn't freak out, but do get the colonoscopy.

HDL in the 90's? You rock!