Allen test
Pronunciation: AL-en
Clinical examination to assess collateral circulation between radial and ulnar arteries in the hand.
Full Definition
The Allen test is a simple bedside examination used to evaluate the adequacy of collateral arterial circulation in the hand before procedures that may compromise radial or ulnar artery flow. The test involves occluding both the radial and ulnar arteries while the patient makes a fist to drain blood from the hand. The hand is then opened and one artery is released while maintaining pressure on the other. Normal capillary refill (within 5-7 seconds) indicates adequate collateral flow through the patent artery. This test is particularly important before radial artery harvesting for cardiac procedures or arterial line placement.
Usage
Usage note: Named after Edgar Van Nuys Allen; capitalize when referring to the eponymous test.
In Context
- "The Allen test was positive, confirming adequate ulnar artery collateral circulation." — Pre-operative assessment
- "A negative Allen test contraindicated radial artery cannulation for blood pressure monitoring." — Anesthesia consultation