Question

3. You are performing a modified Allen's test to the right arm on Ms. Gordon, a 22-year-old African American woman. You notice that her fingertips are cold to the touch. After release of the ulnar artery, it takes 12 seconds for color to re- turn to the palm. What actions should you take at this time? What are the possible causes of a negative Allen's test in this patient?

Answer 1

3. Allen test is the one used to assess the arterial blood flow to the hands. After releasing pressure on the ulnar artery, the hand becomes warm and flushes with the return of blood flow within 5 to 15 seconds. If it took greater than 15 seconds then it is negative which means a single artery (ulnar) will not be sufficient to supply enough blood to the hands.

In this case, the immediate action is to perform the Allen test in another arm. Otherwise, repeat the test after sometimes or make the patient hand be warmed before the test to confirm the test results.

The possible causes for negative Allen's test are

• excessive cold causes constriction of blood vessels.
• Miscompression
• Occlusion of both radial and ulnar artery.
• Lack of blood flow to the peripheral arteries.
• blood vessel spasm