Final answer:
Ethylenediaminetetraacetic acid (EDTA) is an anticoagulant used in blood collection tubes to prevent clot formation by binding calcium ions. Additionally, EDTA is utilized in treating heavy metal poisoning through its chelating properties to form water-soluble complexes that are then excreted. The correct answer is (A) Anticoagulant added to blood tubes.
Step-by-step explanation:
Ethylenediaminetetraacetic acid, commonly known as EDTA, is a compound used as an anticoagulant in blood collection tubes. When blood is collected into tubes containing EDTA, it acts to bind calcium ions, thereby inhibiting the blood coagulation cascade and preventing clot formation. This action ensures that the blood remains in a liquid state so that plasma can be separated by centrifugation for various tests and analyses. The removal of calcium is crucial as it is a key factor in the clotting process, where it helps in the conversion of prothrombin into thrombin and promotes the production of thromboplastin.
Through its chelating properties, EDTA is also used in clinical settings to treat heavy metal poisoning. It binds tightly to metal ions and forms water-soluble chelates which can then be excreted by the kidneys. This function underscores its utility in treating patients with heavy metal toxicity as it facilitates the elimination of these toxic substances from the body.