Which assessment is used to ensure adequate ulnar collateral circulation before radial artery harvest?

• A. Allen test or Doppler.
• B. EKG.
• C. CT angiography.
• D. Pulmonary function test.

Answer: (A)

Before harvesting the radial artery, you must confirm the hand will still receive adequate blood supply if that artery is removed. The most common way to check this is the Allen test. It involves temporarily occluding both the radial and ulnar arteries while the patient makes a fist to drain blood from the hand, then releasing one artery to see how quickly color returns. If perfusion returns promptly via the ulnar artery and palmar arch, the hand should tolerate radial artery harvest. Doppler ultrasonography can complement this by providing objective evidence of blood flow in the ulnar artery and palmar arches, confirming patency and adequate collateral circulation. The other tests listed do not assess hand perfusion or collateral flow and are not appropriate for this purpose.