National Phlebotomy Certification Practice Exam

When a specific volume of whole blood, such as 5cc, is required for a special test, the choice of the tube is crucial to ensure that there is enough blood to perform the test accurately and without any issues. A 5 mL tube is the appropriate choice because it can accommodate the exact volume needed while also providing a slight excess, which helps prevent issues such as overfilling, contamination, or inadequate sample processing.

Choosing a tube that holds a volume equal to or greater than the required sample ensures that the laboratory has sufficient material to work with, typically allowing for any necessary repeat testing or adjustments. Tubes that hold significantly less, such as those holding 3 mL, would be insufficient for the sample size needed, potentially leading to compromised test results or invalid tests. Similarly, while tubes with larger capacities like 10 mL or 15 mL could technically hold the required sample, they do not match the exact need and may lead to unnecessary waste of material and resources.