Allen’s Test (Wrist)

Allen’s Test (and its Modified version) is a physical exam to assess arterial blood flow and collateral circulation of the hand. More specifically, whether both the radial and ulnar arteries adequately supply the hand. This test is essential before surgical procedures, arterial cannulation, or in cases of vascular compromise to ensure the safety of occluding either artery.

How the Test is Performed

The client makes a tight fist for about 30 seconds to exsanguinate the hand.

The therapist occludes both the radial and ulnar arteries at the wrist using firm pressure.

The client relaxes and opens the hand, which should appear pale or blanched.

Pressure on one artery (usually the ulnar) is released while the other remains compressed.

Positive sign: The hand rapidly returns to normal color within 5–15 seconds, indicating adequate collateral circulation and a patent ulnar artery.

The test can be repeated for the radial artery by reversing which artery is released.

Negative sign: If the hand remains pale after release, arterial supply is insufficient. Risk of ischemic complications if the compressed artery is occluded.

Both sides should be compared.

 Allen's Test (Wrist)
Allen's Test for the wrist

Clinical Significance

  • The Allen’s Test determines if the hand can be safely supplied by collateral vessels if one major artery is compromised (by surgery, cannulation, injury, or occlusion).

  • It helps screen for vascular insufficiency, Raynaud’s phenomenon, or risk after trauma or cyst removal.

  • A positive test is required before procedures that may disrupt arterial blood flow (e.g., radial artery line placement, flap harvest).

Assessment

  • Use Allen’s Test when clients present with hand pain, numbness, coldness, vascular symptoms, history of wrist trauma, or before recommending deep work over the wrist arteries.

  • Document test results, noting time to color return and side-to-side comparison for clear records and interprofessional sharing.

Treatment

  • If test is positive (normal):

    • Gentle massage is generally safe, but avoid excessively deep or compressive techniques over the radial or ulnar arteries in hyper-sensitive, post-surgical, or vascular-compromised clients.

  • If test is negative (abnormal):

    • Do NOT apply deep or prolonged pressure over the compromised vessel.

    • Avoid heat, strong mobilization, or aggressive work in clients with poor collateral flow or vascular disease.

    • Educate the client about vascular health, position changes, and the need for referral if symptoms persist.

Safety and Referral

  • Refer clients for further vascular evaluation if the test is negative or if symptoms suggest acute or chronic arterial compromise (persistent pallor, delayed capillary refill, severe coldness, pain).

  • Collaborate with physicians for perioperative, post-traumatic, or vascular pathology cases.