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Allens Test

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Other Names

  • Allen’s Test
  • Modified Allen test
  • MAT

Purpose

The ‘reverse’ Allen’s test. a. The pallor associated with occlusion of both radial and ulnar artery inflow to the hand. b. Rapid return of redness to the hand following release of radial artery pressure confirming flow through the radial artery[1]
Illustration of the modified Allens Test[2]
  • Assess patency of arterial blood supply of hand
  • Anatomy: Ulnar Artery, Radial Artery
  • First described in 1929 by Edgar V. Allen (need citation)

Description

Modified Allens Test

  • The patient is seated or standing
  • Palpate the radial artery with one hand, and the ulnar artery with the other
  • Apply compression to both arteries and ask the patient to clench and unclench hand 10 times
  • Release the ulnar artery and measure the time it takes for the thenar eminence to become flushed
  • Repeat the test with the radial artery
  • Compare to the unaffected hand
  • Positive test
    • Delayed capillary refill, typically > 6 seconds

Original Allens Test

  • Performed by asking the patient to elevate both arms above the head
  • This was to exsanguinate the hands
  • Then the patient is asked to squeeze their hands into tight fists
  • The examiner then occludes the radial artery simultaneously on both hands
  • The patient then opens both hands rapidly
  • Positive test
    • Failure of the initial pallor to return to normal color

Pathology


Evidence

Thoracic Outlet Syndrome

  • Using a 6 second cutoff[3]
    • Sensitivity: 54.5%
    • Specificity: 91.7%
    • Diagnostic accuracy: 78.5%

See Also


References

  1. Foreman, Andrew, et al. "The Allen’s test: revisiting the importance of bidirectional testing to determine candidacy and design of radial forearm free flap harvest in the era of trans radial endovascular access procedures." Journal of Otolaryngology-Head & Neck Surgery 44.1 (2015): 1-5.
  2. Castro, Danny, Sachin M. Patil, and Michael Keenaghan. "Arterial blood gas." (2019).
  3. A. Martin et al. Reliability of Allen’s test in selection of patients for radial artery harvest, The society of thoracic surgeons. Ann Thorac Surg 2000;70:1362-1365
Created by:
John Kiel on 23 July 2019 23:45:22
Authors:
Last edited:
24 March 2023 06:43:18
Category: