Blood tests...sigh...once had three different nurses in my urologist's office stick me a total of four times before they could get one little vial of blood for a PSA test. In the process, one of the nurses stuck herself with one ef the used needles, so she and I both had to be tested for HIV. I told them to test mine from the vial they just obtained. The next time I went to that doctor, she (the careless nurse) was no longer employed there.
As for gallstones, I recommend having the gall bladder removed (cholecystectomy). It can be done laparoscopically with three or four tiny incisions. Mine was an outpatient affair taking about four hours from check-in to heading home. See: http://www.webmd.com...-for-gallstones
The gall bladder's only purpose is to store excess bile. Who needs that?
Good luck! If it hurts, get rid of it.