Final answer:
Blood gas analyses need to be performed promptly, generally within 15 minutes of collection, to ensure accurate results as blood levels of gases like oxygen and carbon dioxide can change quickly due to cellular metabolism.
Step-by-step explanation:
The sample that needs to be run within 15 minutes of collection is most likely a blood gas analysis or a lactate measurement. These tests are time-sensitive because the levels of oxygen, carbon dioxide, and lactate in the blood can change rapidly once the blood is drawn due to ongoing cellular metabolism. Therefore, proper handling and rapid analysis are crucial to ensure the accuracy of the test results.
Blood gas analyses are typically performed on blood samples collected into tubes containing anticoagulants such as K2EDTA or lithium heparin and must be processed immediately. In a scenario where a lab technician collects a blood sample in a glass tube and lets it sit for about an hour, the blood would clot, and serum is obtained after centrifugation, which is different from processing for blood gases where plasma is required. In the context of experimental pharmacokinetics studies, it is noted that complete sample preparation for bioanalysis such as that of blood samples can involve centrifugation to obtain plasma, addition of methanol or other solvents, and homogenizing steps, depending on the matrix such as feces or urine.