Below is an instruction from Human. Write a response.
    ### Instruction:
    How to diagnose Gallstones ?
    ### Response:
    A health care provider will usually order an ultrasound exam to diagnose gallstones. Other imaging tests may also be used.
                
- Ultrasound exam. Ultrasound uses a device, called a transducer, that bounces safe, painless sound waves off organs to create an image of their structure.
    