"Component Separation" of Blood bags: How to Separate plasma from Red blood Cells through Centrifuge layer Design

Blood bags achieve the separation of plasma and red blood cells through the design of a centrifugal layer, mainly based on the density differences of blood components. By using a centrifuge to generate a centrifugal force field, components of different densities produce different sedimentation rates. The specific separation process and principle are as follows:

I. Separation Process

\ n1. Blood Collection and Centrifugation Preparation: Place the collected blood samples into the centrifuge tubes of the centrifuge.

2. Centrifugation operation: When a centrifuge rotates at high speed, it generates a powerful centrifugal force field. Substances of different densities will move along the direction of the centrifugal force.

3. Component stratification: Due to the red blood cell density (approximately 1.096/1.101 g/cm ³) Greater than plasma density (approximately 1.025-1.030 g/cm ³) Red blood cells are subjected to a greater centrifugal force and will settle to the bottom of the centrifuge tube at a faster speed. However, the density of plasma is relatively small. During the process of erythrocyte sedimentation, it will gradually accumulate at the upper part of the centrifuge tube. After a certain period of centrifugation, the blood sample will be clearly divided into two layers. The upper layer is light yellow plasma, and the lower layer is a deep red layer of red blood cells. Between the two layers, there may also be a very thin layer of grayish-white substance, mainly consisting of white blood cells and platelets.

Ii. Key Points for Centrifuge Layer Design

\ n1. Centrifuge Selection and Parameter Setting: Use a low-temperature centrifuge with a swinging cup to centrifuge whole blood. The speed is usually around 5000×g, and the temperature is controlled at around 5℃ (the specific time and conditions may vary depending on different equipment and operation specifications).

2. Blood bag design: Blood bags typically adopt a multi-layer structure, which can maintain good morphological stability during the centrifugation process, ensuring that blood components can be normally stratified under the action of centrifugal force. Meanwhile, the material of the blood bag should be capable of withstanding the pressure and friction during the centrifugation process to prevent rupture or leakage.

3. Supporting equipment and operation norms: During the centrifugation process, it may also be necessary to use blood bag extruders and other equipment in conjunction to transfer and collect components such as upper plasma or lower red blood cells. During the operation, it is necessary to strictly follow the aseptic operation norms to ensure the quality and safety of the blood components.