Allen Test | Hand Vascularization | Radial & Ulnar Artery Assessment
The Allen Test assesses for blood circulation in the hand. Jarvis et al. (2000) have evaluated Allen’s Test accuracy to distinguish between healthy and impaired arteries in order to select the radial artery for coronary bypass surgery. They found the following sensitivity and specificity values for different cut-off times:
- 6 seconds: 54,5% sensitivity and 91,7% specificity
- 5 seconds: 79,6% sensitivity and 75,8% specificity
- 3 seconds: 100% sensitivity and 27% specificity
They concluded that at no cut-off point, the Allen test performed satisfactorily as a discriminatory test and that a Doppler ultrasound device should be used instead.
To conduct the test, ask your patient to open and close the hand several times as quickly as possible and then squeeze the hand tightly then compress the radial and the ulnar arteries with your thumbs. Hold it quickly and then ask your patient to open the hand and release the radial artery and you can see how the blood is streaming back into the hand quickly.
We will now repeat the same process and release the ulnar artery. This test determines the patency of the ulnar and radial arteries. With a healthy artery, the blood should stream back into the hand quickly indicated by the red color.
Make sure to always compare both hands to determine if an artery is impaired.
Another common test to assess digital blood flow is the digital blood flow test.
21 OF THE MOST USEFUL ORTHOPAEDIC TESTS IN CLINICAL PRACTICE
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