Dr. O’Brien is an excellent diagnostician. He is a doctor who intently listens to his patients then, thoughtfully asks questions. Often he’ll consult a web site that can help me but most often he quickly diagnoses the problem. He is never hesitant to consult another doctor if necessary, or order tests to aid in his diagnosis. He also recommends specialists who treat specific ailments or conditions. Dr. O’Brien is an excellent doctor who performs his vocation very efficiently & effectively. We’re very pleased to be in his service.