Which tube top color is associated with potassium oxalate and sodium fluoride additives?

The color associated with potassium oxalate and sodium fluoride additives in tubes is gray. Potassium oxalate acts as an anticoagulant by binding calcium in the blood, while sodium fluoride serves as a preservative that inhibits glycolysis, thus preserving glucose levels in the sample. This combination is particularly useful for tests that require accurate measurement of glucose levels in whole blood or plasma, as it helps prevent any cellular breakdown that could falsely elevate glucose results.

The gray-top tubes are specifically designed for such tests where glucose preservation is vital, making them the standard choice for glucose testing and other specific assays requiring this combination of additives.