Below is an instruction from Human. Write a response.
    ### Instruction:
    How to diagnose Tetralogy of Fallot ?
    ### Response:
    Doctors diagnose tetralogy of Fallot based on a baby's signs and symptoms, a physical exam, and the results from tests and procedures.
                
Signs and symptoms of the heart defect usually occur during the first weeks of life. Your infant's doctor may notice signs or symptoms during a routine checkup.
    