Physical Exam

Allen Test

also known as Modified Allen test

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Video coming September 2026

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

Incomplete Palmar Arch

Abnormal modified Allen test

Rule in

Very helpfulDerived CI

Rule out

Somewhat helpfulDerived CI

Evidence:Strong

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. Fiabilidad y validez del test modificado de Allen: una revisión sistemática y metaanálisis [Reliability and validity of the modified Allen test: a systematic review and meta-analysis]. Emergencias. 2017;29(2):126-135. PMID 28825257.
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):237-244.
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.
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.

Research last updated September 9, 2026.