Allen's test: does it have any significance in current practice?

Percutaneous coronary intervention (PCI) performed through transradial access (TRA) has been consistently demonstrated to be safer than transfemoral access (TFA), mainly due to significantly reduced bleeding and vascular complications. Despite demonstrating better patient safety, acceptance of TRA as an access site of choice has remained low, with geographical variations. One of the relative contraindications to performing PCI through TRA is an abnormal Allen's test (AT), in which case the access site is usually switched to TFA. Bleeding and vascular complications are the "Achilles heel" for interventions through the TFA. The use of the AT is controversial given its low sensitivity in assessing both the collateral circulation of the hand and predicting ischemic complications. In this article, we present interesting data from the congenital heart and trauma literature that lead us to suggest the AT is an inadequate test to assess the collateral circulation of the hand. We think the case for its routine guideline-driven use is flawed.