NHA Phlebotomy Certification Practice Exam

When should arterial blood gases be placed on ice after collection?

1. Immediate refrigeration

2. Within 30 minutes

3. Within 60 minutes

4. Within 2 hours

The correct answer is: Within 30 minutes

Proper handling of arterial blood gases (ABGs) is critical to ensure accurate analysis. After collection, it is essential to place the arterial blood gas sample on ice within 30 minutes to preserve its integrity and prevent metabolic changes. When blood samples are collected, particularly for gases, they are highly sensitive to changes in temperature, metabolism, and exposure to air. Delaying the cooling of the sample can lead to alterations in pH, pCO2, and pO2 levels due to cellular metabolism which continues even after the blood has been drawn. This can affect the diagnostic accuracy of the results. The guideline to place the sample on ice within 30 minutes helps maintain the temperature and minimize metabolic activity, thereby ensuring that the results reflect the patient's physiological state at the time of collection. This is critical in scenarios involving respiratory or metabolic disorders where precise blood gas data is needed for effective treatment. In comparison, refrigerating the sample immediately or later than 30 minutes could lead to inaccuracies due to ongoing biochemical reactions, highlighting why timely action is essential in the handling of ABG samples.