What is the maximum recommended storage time and temperature for an arterial blood gas sample drawn in a plastic syringe?

The maximum recommended storage time and temperature for an arterial blood gas (ABG) sample drawn in a plastic syringe is crucial for maintaining the integrity of the sample. The correct choice indicates that the sample can be stored for up to 30 minutes at room temperature, which is approximately 22°C.

When an ABG sample is exposed to air or stored improperly, several factors can alter its chemical composition, primarily affecting the partial pressures of gases like oxygen and carbon dioxide, as well as pH levels. Storing the sample at room temperature for a limited time helps to minimize changes caused by metabolism of the blood cells, provided that it's done within the recommended timeframe.

Choosing a longer storage time or lower temperatures may not be as effective for the accuracy of the results, since cooler temperatures may slow down metabolic processes, but they can lead to different types of alteration in sample dynamics or affect the gas solubility in the plasma. Thus, maintaining the sample at room temperature for this specified period ensures that it is analyzed while the changes are still predictable and limited.

In contrast, the other time and temperature combinations presented would either risk significant alterations to the sample’s properties or exceed recommended protocols, which would compromise the test results.