Editing Allen's test (section)

===Modified test===
In the modified Allen test, one hand is examined at a time:<ref name=":0" />
# The patient is asked to clench their fist for about 30 seconds.
# Pressure is applied over the ulnar and the radial arteries so as to occlude both of them.
# Still elevated, the hand is then opened. It should appear blanched (pallor may be observed at the finger nails).
# Ulnar pressure is released while radial pressure is maintained, and the colour should return within 5 to 15 seconds.

If color returns as described, Allen's test is considered to be normal. If color fails to return, the test is considered abnormal and it suggests that the [[ulnar artery]] supply to the hand is not sufficient.<ref name=":0">{{Cite web|title = Modified Allen test|url = https://www.ncbi.nlm.nih.gov/books/NBK138652/|date = 2010-01-01|last1 = National Center for Biotechnology|agency = U. S. National Library of Medicine|publisher = World Health Organization}}</ref>