You are required to draw blood from a patient and to keep it in a test tube for analysis of blood corpuscles and plasma. You are also provided with the following four types of test tubes. Which of these will you not use for the purpose?

Step-by-step solution

Calcium bicarbonate causes clotting of blood. Chilled test tube decrease the rate of coagulation of blood. Chelating agents like heparin, EDTA, sodium oxalate act as anti-coagulants. Related Theory Clotting requires calcium ions ( Ca ²⁺ ) and chelating agents bind to free metal ions, such as calcium, so the blood will not clot.