What is the Allen Test?

The Allen test is a method of examination physicians use to examine arterial blood flow into the hands. Edgar Van Nuys Allen described the original test in 1929. In 1952, however, Irving S. Wright suggested an alternative test that has largely replaced the original in modern medical practice. Professionals often refer to the newer test as the modified Allen test. Over the many years since doctors incorporated the modern test, physicians have attempted many adjustments. However, few have excelled in popularity like the originals.

1. Original Test

The original Allen test is straightforward and has only a few steps:

1. A physician asks their patient to elevate both arms and clench both fists tightly for one minute.
2. He then applies pressure over both radial arteries in the patient's wrists, to block blood flow.
3. While the doctor is blocking the arteries, the patient opens their hands rapidly. The doctor then examines the color of both hands.
4. Repeating the test enables doctors to study the ulnar arteries, as well.

The ultimate goal of the test is to identify abnormal circulation.