 [ Symptoms ] i had infection in left upper leg if antibiotics were needed no idea where in fection came from i have hardware in leg from surgery seven years ago could this cause it have difficult being on it for long time and trouble walking [ Disease ] the allen test is used to check the health of the ulnar artery and other vessels in the hand that maintain normal circulation it is executed by first allowing blood to drain from the hand at the end blood flow to the hand is evaluated first ask the patient to hold a clenched fist high in the air at the same time the main arteries are compressed by compressing the ulnar and radial artery you allow blood to drain from the hand next lower the hand and open the fist once pressure is release color should flow bak into the hand this indicates that the ulnar vessel is healthy