Which statement is correct regarding sample storage for the prothrombin time test?

Prothrombin time (PT) testing is sensitive to the handling and storage of blood samples, particularly how long they can remain stable for accurate results. The correct statement is that the sample is stable for 24 hours if capped, which indicates that proper sealing of the sample tube helps to preserve the integrity of the specimen for an extended period.

When a blood sample is collected for PT testing, certain factors, such as exposure to air and temperature fluctuations, can affect the coagulation factors within the plasma. Capping the sample ensures minimal exposure to these external factors, thereby maintaining its stability for up to 24 hours at room temperature.

Refrigeration, while it may extend the lifespan of some samples, does not guarantee the same stability period for PT as capping does. Samples stored in the refrigerator may not maintain accurate results over the same time frame as those that are properly capped at room temperature. Thus, while temperature control is critical for many lab analyses, it does not take precedence over proper storage methods like capping. This understanding is vital for laboratory practitioners to ensure accurate coagulation profiling and patient management.