A medical assistant needs to draw a blood glucose level on a patient. Which of the following tubes should they use?

• A. Red top tube
• B. Blue top tube
• C. Gray top tube
• D. Green top tube

Answer: (C)

The gray top tube is the appropriate choice for drawing a blood glucose level due to its additive, specifically potassium oxalate and sodium fluoride. These are essential for glycolysis inhibition, preventing the breakdown of glucose by cells in the blood sample after it has been drawn. The fluoride acts as a glucose preservative, ensuring accurate results by maintaining the glucose levels in the sample over time.

The other tubes have different additives and uses that make them less suitable for this specific test. The red top tube does not contain any additives, making it not ideal for preserving glucose levels. The blue top tube contains sodium citrate, which is used mainly for coagulation studies rather than glucose testing. The green top tube includes heparin, which is primarily useful for plasma tests, not specifically for glucose monitoring. Thus, the best choice for accurately measuring a blood glucose level is the gray top tube.