The first step in diagnosing the condition is a physical examination by the doctor who will try to look into your pattern of breathing. The doctor may also record your medical history.
The doctor will also need to rule out other factors, if any, that may be causing hyperventilation. He may order the following tests
Arterial blood sample / other blood tests
Chest X-ray / CT scan
Ventilation perfusion scan
If the doctor suspects a serious cause then further tests may be ordered.