Physical examination maneuver

Physical Exam

Allen Test

also known as Modified Allen test
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How to Perform

Ask the patient to clench the fist while you occlude both the radial and ulnar arteries at the wrist with firm pressure. Have the patient open the hand, which should appear pale, then release pressure over the ulnar artery while maintaining radial compression and watch for the return of color to the hand. Repeat, releasing the radial side. Color returning within a few seconds is a normal result; color that fails to return (the palm stays pale) is an abnormal result.

How to Interpret

Showing 3 of 4 findings

Incomplete Palmar Arch

Abnormal modified Allen test
Rule in
Very helpfulDerived CI
Rule out
Somewhat helpfulDerived CI
Evidence:Strong

Radial Artery Occlusion

Failure of palmar reperfusion on release of the radial artery
Rule in
Somewhat helpfulWide CI
Rule out
Minimally helpful
Evidence:Moderate

Ulnar Artery Occlusion

Failure of palmar reperfusion on release of the ulnar artery
Rule in
Somewhat helpfulNo CI
Rule out
InconclusiveWide CI
Evidence:Moderate

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Related Systems / Regions

CardiovascularUpper ExtremitiesWrist and Hand

Related Diagnoses

Hand IschemiaIncomplete Palmar ArchRadial Artery OcclusionUlnar Artery Occlusion

Related Chief Complaints

Absent Wrist PulseBlue FingersCold FingersCold HandFinger UlcersHand PainHand Pain After an Arterial LineHand Pain with UseIncidental FindingMottled HandNumb FingersPainful FingersPale FingersPale HandPoor Color Return in the HandPre-procedure AssessmentProlonged Pallor of the HandWeak Hand After a Blood Draw

References

  • Romeu-Bordas Ó, Ballesteros-Peña S. Validez y fiabilidad del test modificado de Allen: una revisión sistemática y metanálisis [Reliability and validity of the modified Allen test: a systematic review and meta-analysis]. Emergencias. 2017;29(2):126-135. PMID 28825257. Free full text: revistaemergencias.org.
  • Romeu-Bordas Ó, Ballesteros-Peña S. Validez y fiabilidad del test modificado de Allen: una revisión sistemática y metanálisis [Reliability and validity of the modified Allen test: a systematic review and meta-analysis]. Emergencias. 2017;29(2):126-135. PMID 28825257.
  • Di Santo P, Harnett DT, Simard T, Ramirez FD, Pourdjabbar A, Yousef A, et al. Photoplethysmography using a smartphone application for assessment of ulnar artery patency: a randomized clinical trial. CMAJ. 2018;190(13):E380-E388. doi:10.1503/cmaj.170432. PMID: 29615421. PMCID: PMC5880645.
  • Allen EV. Thromboangiitis obliterans: methods of diagnosis of chronic occlusive arterial lesions distal to the wrist with illustrative cases. Am J Med Sci. 1929;178(2):237-243.

Research last updated September 9, 2026.