If your doctor suspects PCOS, s/he may refer you to a gynaecologist(a specialist in women's reproductive health).Your doctor will look for the signs of PCOS and rule out other problems that cause similar symptoms. Common tests include blood tests-to check thyroid function and measure your level of glucose and hormones, eg testosterone; an ultrasound scan-to see if your ovaries are enlarged and /or polycystic. Having cysts on your ovaries doesn't necessarily mean you have PCOS. It's also possible that you will be diagnosed with PCOS even if you don't have any cysts on your ovaries.
Attribution: BUPA