What is the antiglycolytic agent found in a gray top tube?

The gray top tube contains sodium fluoride as its antiglycolytic agent. Sodium fluoride is used primarily to preserve glucose in blood samples by inhibiting glycolysis, the metabolic process wherein glucose is broken down by cells. This is particularly important for tests requiring accurate glucose measurements, as any cellular metabolism can lead to a decrease in the glucose concentration in the sample over time.

While the other agents listed serve important roles in different types of blood collection tubes, they do not have the primary function of preserving glucose. Lithium heparin and EDTA act as anticoagulants, preventing blood from clotting and thereby suitable for different tests that require serum or plasma. Potassium oxalate also acts as an anticoagulant and is commonly used in conjunction with sodium fluoride, but it doesn’t serve the same role as an antiglycolytic agent. Therefore, sodium fluoride's specific function in the gray top tube is crucial for maintaining the integrity of glucose levels in the sample for accurate laboratory analysis.