American Society for Clinical Pathology (ASCP) Histotechnician Certification Practice Exam

When collecting blood for arterial blood gases (ABGs), why is it unnecessary to pull the plunger of the syringe?

1. Arterial blood is under pressure from the contraction of the ventricles

2. The blood will coagulate if the plunger is pulled

3. The syringe is pre-filled with anticoagulant

4. Venous blood is being collected instead

The correct answer is: Arterial blood is under pressure from the contraction of the ventricles

When collecting blood for arterial blood gases (ABGs), it is unnecessary to pull the plunger of the syringe because arterial blood is under pressure due to the contractions of the ventricles in the heart. This pressure allows the blood to naturally fill the syringe without the need for manual suction. Arterial blood is more oxygenated and is being pushed through the arteries at a higher pressure compared to venous blood, which can lead to complications or inaccurate results if suction is applied. The other options do not accurately reflect the principles of blood collection for ABGs. For instance, although anticoagulants are often used for specific blood tests, the typical collection for ABGs involves a syringe designed to keep the sample intact without manually pulling the plunger. Similarly, the status of coagulation does not directly relate to the act of pulling the plunger in the context of arterial blood. Lastly, this procedure specifically targets arterial blood, and venous blood is collected using a different technique that would not involve the same precautions.