Anticoagulants in blood bank

UNIT III

Anticoagulants used in blood bank, Types and composition of various anticoagulants

Advantages and disadvantages of various anticoagulants

       Anticoagulants used in blood bank

Anticoagulants are chemicals to prevent blood clotting. They are used in blood samples in the laboratory and collected blood unit during storage in the blood bank. They increase blood cell viability.

The following are the most commonly used anticoagulants in blood banks.

• 1. Ethylene diamine tetra acetic Acid (EDTA): EDTA is a chelating agent that binds with calcium ions. Calcium ion is essential for blood clotting. Calcium ions shall not be available for blood clotting because EDTA binds with calcium ions. EDTA is commonly used in blood banking.

• 2. Citrate: Sodium citrate is a commonly used anticoagulant. It binds with calcium ions in the blood to prevent blood clotting. It is used in a ratio of one part sodium citrate and 9 part blood. Sodium citrate is used to prepare anticoagulant preservative solutions such as ACD (Acid citrate dextrose) and CPD (Citrate phosphate dextrose).

• 3. Double oxalate: Double oxalate is a mixture of ammonium oxalate and potassium oxalate. They bind with calcium ions in the blood to stop blood clotting.

• 4. Heparin: Heparin is a natural anticoagulant. It enhances antithrombin III activity that prevents several clotting factors. It is commonly used in blood banking, especially in platelet collection for transfusion.

• 5. ACD A (Acid citrate dextrose solution A): It is the anticoagulant preservative solution. It is used in the collection and storage of whole blood. It contains citrate that prevents blood clotting. Its dextrose provides nutrition to blood cells during storage.

• 6. CPD-1 (Citrate phosphate dextrose adenine 1): It is also the anticoagulant preservative solution. It is used in the collection and storage of whole blood. It contains citrate, phosphate dextrose, and adenine. Adenine helps to maintain the viability of red blood cells. CPD is preferred over ACD because CPD isotonicity and pH is nearer to blood pH and isotonicity. Thus, RBC survival in CPD is better than in ACD.

• Types and composition of various anticoagulants

• 1. Type: Chelating Anticoagulant: Example: Ethylene diamine tetra acetic Acid (EDTA)

  Composition: EDTA anticoagulant is available as disodium EDTA and trisodium EDTA. They act as chelating agents and bind with calcium ions. They prevent blood clotting by stopping calcium ions.

  • EDTA (disodium EDTA or

  • trisodium EDTA.): 150 mg

  • Distilled water: 100mL.

• Composition of Sodium oxalate: It is used as in 1:9 ratio of sodium citrate and blood.

• Composition of Double oxalate:

  • Ammonium oxalate: 2.4 gm

  • Potassium oxalate: 1.6 gm

  • Distilled water: 100 mL

• 2. Type: Citrate Anticoagulant and preservative. Examples: ACD, ACD-A and CPD, CPD-A.

  Composition of ACD: Sodium citrate is a commonly used anticoagulant. It binds with calcium ions to prevent blood clotting. Trisodium citrate, citric acid, dextrose, and distilled water are used in ACD solution.

  • Trisodium citrate: 2.2 gm

  • Citric acid: 0.8 gm

  • Dextrose: 2.46 gm

  • Distilled water: 100 mL

• Composition of ACD-A

  • Trisodium citrate: 2.2 gm

  • Citric acid: 0.8 gm

  • Dextrose: 2.46 gm

  • Adenine: 0.02 gm

  • Distilled water: 100 mL

• Composition of CPD

  • Trisodium citrate: 2.6 gm

  • Citric acid: 0.3 gm

  • Dextrose: 2.5 gm

  • Distilled water: 100 mL

• Composition of CPD-A

  • Trisodium citrate: 2.6 gm

  • Citric acid: 0.3 gm

  • Dextrose: 2.5 gm

  • Adenine: 0.02 gm

  • Distilled water: 100 mL

• 3. Type: Natural anticoagulant. Example: Heparin

• Composition: It is a naturally occurring anticoagulant obtained from animals.

Advantages and disadvantages of various anticoagulants

• A. Tri sodium citrate: It is the most commonly used anticoagulant in blood banking. It has the following advantages and disadvantages.

  Advantages

  • 1. Effective: Sodium citrate effectively prevents blood clotting to maintain blood fluidity.

  • 2. Cell viability: Sodium citrate maintains the viability of blood cells and other cellular components during storage.

  • 3. Compatible: Sodium citrate is widely used in laboratory tests. It does not interfere with the blood testing report.

  • 4. Economical: It is an easily available and inexpensive anticoagulant.

  Disadvantages

  • 1. It affects some blood parameters such as calcium content and platelet function

  • 2. Incompatibility: It is incompatible in certain laboratory tests that depend upon calcium reactions.

  • 3. Short self-life: Sodium citrate has a limited shelf-life.

  • 4. It requires an accurate sodium citrate: blood ratio to produce an anticoagulant effect.

• B. EDTA

  Advantages

  • 1. Effective: It is a very effective chelating agent. It very effectively binds with calcium to prevent blood clotting.

  • 2. Stability of blood parameters: It effectively maintains blood parameters during blood storage and testing.

  • 3. Widely used: It is the most commonly used anticoagulant. It is used in a wide range of medical laboratory tests.

  • 4. Preservation of cellular morphology: It preserves the morphology of red blood cells and other blood cells.5. Economical: It is easily available at a very affordable cost

• Disadvantages:

  • 1. Incompatibility: It is incompatible in certain laboratory tests that depend upon calcium reactions or metal ion-dependent enzyme

  • 2. Cellular alteration: It can change blood cell morphology if not used in proper concentration.

  • 3. Short self life: EDTA has limited self life Thus it preserves blood for a shorter duration.

  • 4. Platelet aggregation inhibition: EDTA inhibits platelet aggregation. It is not required under certain conditions such as assessment of platelet functions.

  • 5. Calcium chelation: EDTA is a chelating agent that binds with calcium to produce an anticoagulant effect. The calcium chelation property of EDTA affects calcium-dependent processes during medical laboratory tests.

• C. Heparin

  Advantages

  • 1. Natural anticoagulant:

  • 2. Potent anticoagulant: It is a highly effective anticoagulant.

  • 3. Rapid onset of action: It has a rapid onset of action. Thus it is most suitable if an immediate anticoagulation effect is required.

  • 4. Reversible anticoagulation: Its anticoagulant effect is reversible.

  • 5. Wide range of applications: It is widely used in the medical field.

  • 6. Minimal impact on medical laboratory tests: Its effect on medical laboratory tests is very low due to minimum chelation property. It does not interfere in medical laboratory tests.

  • 7. Reduced platelet activation: The reduction of platelet activation by heparin is less than other anticoagulants.

  • 8. Easy availability: It is a widely used anticoagulant and easily available for medical laboratory testing.

  Disadvantages

  • 1. It is a costly anticoagulant

  • 2. It affects thyroid hormone testing. The result shows an increased level of thyroid hormone.

  • 3. It develops a blue background in blood smear. This interferes in the microscopic examination of the blood smear.

  • 4. Short self life.

• Dr Pramila Singh