High levels of GGT can be brought on by certain antibiotics (Augmentin) and/or Ibuprofen. I would recommend you see a gastroenterologist. When I was referred over to mine, he was an abudance of information on this topic. I highly suggest it.
Additionally, asymptomatic elevations of liver tests are a frequent cause for consultation to a gastroenterologist or hepatologist. There are many possible causes. Fatty liver, alcohol related liver disease, problems with the bile ducts are among the common cuses for these elevations. Although we usually do not find a serious cause for this elevation, it is necessary to do some tests including an ultrasound of the liver and bile ducts. Sometimes, a liver biopsy is needed for a definitive diagnosis. I suggest that you talk with your doctor about seeing a gastroenterologist