What is a positive Buerger's test result indicative of in a patient with suspected peripheral artery disease (PAD)?

Buerger's Test for Peripheral Arterial Disease

A positive Buerger's test is defined as pallor on elevation for 2 minutes followed by dusky red flush (dependent rubor) upon leg dangling for another 2 minutes (Answer C). 1

Understanding Buerger's Test

Buerger's test is a bedside clinical maneuver used to assess severe distal peripheral arterial disease through observation of color changes in the lower extremities:

Test Procedure and Interpretation

• Elevation phase: The patient lies supine and elevates both legs to 60 degrees for 2 minutes. In severe PAD, the foot becomes pale (pallor) due to inadequate arterial inflow against gravity 1

• Dependent phase: The patient then sits with legs dangling over the edge of the bed. A positive test shows a dusky red flush (dependent rubor) developing within 2 minutes, indicating severe arterial insufficiency and compensatory vasodilation 1

• Normal response: In healthy individuals, the foot maintains normal color during elevation and returns to normal pink color quickly (within 10 seconds) when dependent, without the pathologic rubor 1

Clinical Context and Physical Examination Findings

The presence of elevation pallor and dependent rubor are specific physical examination findings suggestive of PAD that should prompt diagnostic testing with ankle-brachial index (ABI) 1

Other Key Physical Examination Findings in PAD

• Pulse assessment: Lower extremity pulses (femoral, popliteal, dorsalis pedis, posterior tibial) should be palpated and rated as 0 (absent), 1 (diminished), 2 (normal), or 3 (bounding) 1

• Additional signs: Asymmetric hair growth, calf muscle atrophy, nonhealing wounds, and gangrene may accompany severe PAD 1

• Auscultation: Femoral bruits increase the likelihood of PAD when present 2

Why Other Answer Choices Are Incorrect

• Answer A describes measuring blood pressure differences between lower extremities, which is not Buerger's test 1

• Answer B reverses the sequence—it incorrectly states dusky red flush occurs on elevation rather than pallor 1

• Answer D describes the ankle-brachial index (ABI ≤0.90), which is the primary diagnostic test for PAD but is not Buerger's test 1

Diagnostic Confirmation Required

Important caveat: While Buerger's test findings are suggestive of severe PAD, abnormal physical examination findings must always be confirmed with diagnostic testing, typically starting with the resting ABI 1

• An ABI ≤0.90 confirms the diagnosis of PAD 1
• For patients with noncompressible vessels (ABI >1.40), toe-brachial index should be performed 1, 2