Background: Many authors advocate lipase as the preferred serological test for the diagnosis of pancreatitis and a cut-off level of three or more times the upper limit of normal (ULN) is often quoted. The literature contains no systematic review that explores alternative causes of a lipase level over three times as high as the ULN. Such a review was therefore the objective of this study. Methods: The EMBASE and MEDLINE databases (1985 to August 2013) were searched for all eligible articles. Predetermined data were extracted and independently analysed by two reviewers. Results: In total, data from 58 studies were included in the final analysis. The following causes other than pancreatitis of lipase levels exceeding three times the ULN were found: reduced clearance of lipase caused by renal impairment or macrolipase formation; other hepatobiliary, gastroduodenal, intestinal and neoplastic causes; critical illness, including neurosurgical pathology; alternative pancreatic diagnoses, such as non-pathological pancreatic hyperenzymaemia, and miscellaneous causes such as diabetes, drugs and infections. Conclusions: A series of differential diagnoses for significant serum lipase elevations (i.e. exceeding three times the ULN) has been provided by this study. Clinicians should utilize this knowledge in the interpretation and management of patients who have lipase levels over three times as high as the ULN, remaining vigilant for an alternative diagnosis to pancreatitis. The medical officer should be aware of the possibility of incorrect diagnosis in the asymptomatic patient.