Course: Immunohematology
Lab Instructor: Sala Randall
Date: January 22, 2013
Lab #: 1
Title: Cell Washing
Aim: To demonstrate quality assurance techniques in performing cell washing.
Principle: Cell washing is a common procedure performed in the laboratory. This is a series of careful steps taken to wash red blood cells normally three times intermittently with centrifugation and decanting (Harmening 2012). The procedure serves to remove unbound immunoglobulins, Wharton’s jelly (from cord blood), hemolysed cells and also fibrin. The principle of the centrifuge entails centrifugal filtering of components due to centrifugal force applied and also centrifugal sedimentation which allows the separation of these components based on their weight and density due to the gravitational pull (Marieb 2009). In washing red blood cells, quality assurance is ensured so that testing such as cross matching in blood transfusion can be accurately undertaken. The centrifuge used in this exercise was the fixed angle centrifuge. According to Lawrence Kaplan (2003) these rotors are so named due to the fact that the samples are kept at a fixed angle, 25 to 52 degrees of vertical axis of rotation. As the sample rotates, small particles are forced to the sides and bottom on the tube then settles to the bottom due to gravity as rotation ceases. These centrifuges are used when rapid separation of small particles is required.
Materials:
CHEMICAL REAGENTS | APPARATUS & EQUIPTMENT | WaterBlood samples in purple top tube0.85% salineNaCl | Centrifuge5ml Test tubesTest tube rackParafilmDisposable and automatic pipette |
Procedure: Reagent Make-Up and Standard Preparation * 500ml of 0.85% saline was made by dissolving 4.5g of NaCl in 200ml of distilled water then adding up the solution in a measuring cylinder with distilled water until 500ml was obtained. * All the necessary equipments were obtained, checked
References: Harmening D. 2012. Modern Blood Banking & Transfusion Practices. 6th Ed. Philadelphia: FA Davis. p 26. Kaplan LA. Pesce, Armadeo J. 2010. Clinical Chemistry Theory Analysis and Correlation. 5th Ed. Missouri: Mosby Inc. p 23-24. Marieb EN. 2009. Human Anatony and Physiology. Redwood City, Calf: Benjamin Cummings Pub. Co. p 301.