Few prognostic indicators and outcomes reported for patients who have hepatopulmonary syndrome can be consistently reproduced between institutions. The lack of practice recommendations based upon consistent and predictable outcomes creates uncertainty for physicians trying to make the best patient choices. With the scarcity of donor organs, these issues are of particular importance when transplantation in considered as a treatment option. Much uncertainty arises from the basic tasks of making an accurate diagnosis in patients who have symptoms suggestive of hepatopulmonary syndrome. This article focuses on problems that underlie diagnostic accuracy and uses this information to appraise critically outcomes literature.