Usefulness of complementary test in the study of patients with chronic abdominal pain María Isabel Jiménez Candel; Tatiana Salvador Pinto; Mónica García Peris; Elena Crehuá Gaudiza; Carmen Jovaní Casano; María Antonia Moreno Ruiz; Tomás Hernández Bertó; Esther Largo Blanco; Cecilia Martínez Costa;