When your gyn checks you for an ovarian cyst and then asks you to take a blood test for ca-125. Is that a bad sign?

CA 125 - Why check? Cancer antigen 125 (ca-125) is not a screening test for ovarian cancer. It is an adjunctive test for measuring tumor response (ie, a tumor marker) for pts w/ known ovarian cancer. It isn't perfect even when we know someone has ovarian cancer. In the appropriate clinical setting -- eg an abnormal ovary on imaging it might help determine if a mass is benign or malignant, but again is not perfect.
Not necessarily. The doctor may ask for ca125 as another piece of data to help decide what will be the best management for you. That number is used along with the size of the cyst, the complexity of the cyst, the presence of fluid in your abdomen, and your symptoms to decide if surgery is needed, and if so, whether it can safely be done by a general gynecologist of a gyn oncologist.
Yes and No. Significance depends on your age. Ca-125 is a non-specific tumor marker for ovarian cancer (oc). Since oc is rare in younger patients, your age will impact how significant the reasoning may be. It is very non-specific and many things can cause an elevated ca-125. Your doctor will be able to explain this in great detail for you.
Not Necessarily. The ca-125 test has become somewhat of an internet phenom! ca stands for cancer antigen. About 80% of ovarian cancers produce this tumor marker. Often the test is ordered when an ovarian cyst is identified. In many cases it is not appropriate. If you are post menopausal it has greater value in assessing an identified ovarian cyst. It is used to follow ovarian cancer treatment for recurrence.