Which tube color is used for serum testing without additives?

The red tube is specifically designed for serum testing without any additives. This means that blood collected in this tube will clot naturally, allowing for the separation of serum from the cellular components after centrifugation. The absence of additives means that there is no interference with tests that require serum, making it ideal for a variety of laboratory analyses.

In contrast, the other tube colors contain various additives that serve different purposes. For instance, the green tube often contains heparin, which is an anticoagulant that prevents blood from clotting. The lavender tube typically contains EDTA, which is also an anticoagulant used to maintain the integrity of blood samples, particularly for complete blood counts or other hematological testing. The gray tube commonly contains additives like sodium fluoride or potassium oxalate, which are used to preserve glucose and inhibit glycolysis. Therefore, these tubes are not suitable for serum testing without additives, as they would alter the composition of the sample being analyzed.