<prompt> Which among the following can prevent coagulation of blood:Calcium oxalateSodium citrateSodium iodidePotassium chloride  <response>: Ans b: Ref: Guyton 11th edition p466-467Methods to present blood coagulation in vitro1 Siliconized containers - Present contact activation of platelets Factor 82 Heparin - Especially is heart lung machine artificial kidney3 Oxalate compunds - By precipitation of calcium oxalate compounds4 Citrate compoundsSodium citrate, ammonium citrate, potassium citrate- By deionization of blood calcium by forming an unionized calcium compound.But remember citrate anticoagulants are superior to oxalate anticoagulants because oxalate is toxic to body; but moderate quantities of citrate can be injected intravenously 