Body Fluids and Circulation Question 22
22. 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 them will you not use for the purpose?
[2004]
(a) Test tube containing calcium bicarbonate
(b) Chilled test tube
(c) Test tube containing heparin
(d) Test tube containing sodium oxalate
Show Answer
Answer : a
Hints & Solutions
(a) Presence of calcium will remove heparin (blood anti-coagulant) and will promote blood clotting. Sodium oxalate and heparin containing test tubes will not allow the blood to clot. The test is used to monitor heparin therapy to ensure that a person is receiving sufficient heparin for anticoagulation without causing excess bleeding. Since the test involves a chemical reaction color change (colorimetric), it is also known as chromogenic anti-Xa assay or anti-Xa assay.
