Should an Allen test be performed before radial artery cannulation?

Background: This study aims to determine the current status of the Allen test for assessing the circulation of the hand. Methods: The Ovid electronic database was searched using multiple search terms and keywords. Bibliographies of pertinent articles were examined. Data involving results of Allen tests, criteria for abnormality and outcomes, specifically those related to adverse events, were extracted. Results: The criteria for an abnormal Allen test are not agreed upon. The significance of an equivocal or abnormal test is unclear. The test is not accurate in predicting postcannulation hand ischemia. Results of the test suffer from poor interrater reliability. Most critically ill patients cannot cooperate for the performance of the test as described. Conclusions: Performance of an Allen test before radial artery cannulation should not be considered a "standard of care."