I've kind of had this done the other way round. My GP ordered the blood test on the basis of my described symptoms. (Pain in lower abdomen, spotting) I think she was erring on the side of caution as apparently they only do this blood test if they suspect ovarian cancer. So of course I've been freaking out since she rang me the day after the blood test and said it came back with a raised ovarian marker and she was referring me for an ultrasound. Blood test was on 6th December. Ultrasound was today!!

Took the sonologist ten minutes to discover that she could see absolutely no problems with my ovaries. She is sending her report to my GP and asked me to ring the GP next week and discuss where we go from here because she could only tell me what it was not, and my symptoms are still present after over six weeks so something is going on in my body somewhere. 

What I have learned is that a "raised ovarian marker" can have up to 200 causes or can even be a false positive. So my mind has been put at ease on that, at least. 

My GP didn't even tell me what the blood test was. I learned through googling that it was probably the CA125 and that's when I learned that they only do this when they suspect ovarian cancer or even when someone has had ovarian cancer and the bloods test for the effectiveness of treatment. 

So I seem to have dodged the bullet for now. I am not quite sure what the bloods will show for you that they haven't already found on your ultrasound, but then I am not a medic. Try not to worry too much as this blood test seems to be a not terribly accurate one in some cases. I haven't yet found out why they do it other than it is a relatively new type of blood test and they have discovered it has some usefulness in treatment, if not in diagnosis. 

Best wishes to you and try not to dread this blood test too much as it could be just a part of the whole procedure of diagnosis that you are going through.