What is an Allen Test?
The is a medical procedure to assess the hand's arterial blood flow. It was first introduced by Dr. Edgar Van Nuys Allen in 1929. The test is frequently carried out before specific medical operations, such as arterial line placement, to ensure the patient has sufficient blood flow to their hand.
A healthcare professional, usually a nurse or doctor, performs the Allen Test. The clinician compresses the ulnar and radial arteries in the wrist while instructing the patient to clench their hand tightly. The hand turns pale as a result, showing that blood flow has momentarily stopped.
The healthcare professional then instructs the patient to slowly open their hand while only relieving pressure on the ulnar artery. The ulnar artery sufficiently supplies blood flow to the hand if the hand soon returns to normal color. The test is subsequently repeated, but this time the radial artery is the focus of pressure release. The hand should return to its usual color, demonstrating that the radial artery also supplies sufficient blood flow.
If, after releasing one of the arteries, the hand's color does not return to normal, there may be a blockage in that artery or insufficient blood flow. In certain situations, more testing or treatment may be necessary.
The Allen Test is a brief, non-invasive procedure that gives vital details about the hand's arterial blood flow. It is a helpful tool for medical professionals carrying out treatments that can impact blood flow to the hand.











