Which additive is used specifically for whole blood collection?

The correct answer is EDTA, which is commonly used as an anticoagulant in whole blood collection. EDTA stands for ethylenediaminetetraacetic acid, and it works by binding calcium ions in the blood, which are essential for the coagulation process. When collected in tubes containing EDTA, blood specimens remain in a liquid state, allowing for accurate analysis of various blood components without the interference that clot formation would cause.

This is particularly important for specific tests, such as complete blood counts (CBC), where maintaining the integrity of blood cells is crucial for obtaining reliable results. The use of EDTA is essential because it ensures that the sample can be processed for cellular analysis without the confounding factor of clot appearance. In contrast, other additives typically serve different purposes, such as promoting clotting or separating serum from cells, making them unsuitable for whole blood analyses where cellular characteristics need to be preserved.