First, your family doctor will check your testicles and, if there is any cause for concern, he will refer you to a specialist.  An ultrasound scan of the testicles is used to check for any growths.  If any are found, an operation is performed to take a tissue sample from the lump.  This is examined by a pathologist, to determine if the lump is cancerous or not.   Blood test will also be done to check the levels of HCG (human chorionic gonadotrophin) and AFP (alpha fetoprotein), which indicate how advanced the cancer is.