A dentist or physician may notice bad breath during an office visit. Sometimes, the smell of the patient's breath may suggest a likely cause for the problem. For example, "fruity" breath may be a sign of uncontrolled diabetes. A urine-like smell, especially in a person who is at high risk of kidney disease, can sometimes indicate kidney failure.
Your dentist will examine your teeth, gums, mouth and salivary glands. He or she also will feel your head and neck and will evaluate your breath when you exhale from your nose and from your mouth.
Your dentist may refer you to your family physician if a general illness is the most likely cause. You will need diagnostic tests if the doctor suspects a lung infection, diabetes, kidney disease, liver disease or Sjögren's syndrome. The type of tests you get depends on the suspected illness. You may get blood tests, urine tests, X-rays of the chest or sinuses, or other tests.