Before drawing blood for arterial blood gas determinations, which test should the nurse ensure is positive?

The correct choice, which is the Allen test, is critical before drawing blood for arterial blood gas (ABG) determinations because it assesses the collateral circulation in the hand. The Allen test involves compressing both the ulnar and radial arteries while the patient makes a fist. When the patient opens their hand and blood flow is released from one of the arteries, the nurse can observe if the hand flushes with blood, indicating that the other artery has enough collateral circulation to maintain perfusion. A positive Allen test indicates that it is safe to perform the ABG puncture at the radial site, reducing the risk of complications such as ischemia.

Other tests listed have different purposes and are not relevant in the context of preparing for an ABG. The capillary refill test evaluates peripheral perfusion but does not specifically assess arterial blood flow in the context of an ABG procedure. The Trousseau sign is a test for latent tetany and involves checking for carpopedal spasms in response to blood flow restriction; it does not have a direct relationship with the safety of arterial blood draws. The Brudzinski sign is used to assess meningeal irritation, particularly in cases of meningitis, and is not related to blood gas testing. Understanding