Analysis of factors affecting the separation efficiency of serum with separation gel

In clinical testing, the use of separation gel vacuum blood collection tubes is a commonly used method to obtain high-quality serum or plasma samples. The principle relies on the physical properties of the separation gel, which can form a stable isolation layer after centrifugation, effectively separating serum (plasma) from cellular components. However, in practical operation, there are often situations where the separation effect is not ideal, such as incomplete flipping of the gel layer, the presence of fibrin or colloid residues in the serum, etc. The main reasons will be systematically explained below.

1, The key role of separating adhesive material properties

The basis for effective separation of gel is that its density is between serum (plasma) and blood cells. High quality separation adhesive has suitable density and stable thixotropy, which can achieve complete flipping and form a flat isolation layer under centrifugal force. If the quality of the separation gel itself is lacking, the density does not meet the design standards, or its rheological properties are unstable, it may not be fully formed during centrifugation, resulting in some colloids mixing with serum or forming discontinuous isolation zones, directly affecting the clarity and extraction amount of serum.

separation gel

2, The impact of blood stasis on the integrity of coagulation process

One of the prerequisites for determining the separation effect is whether the blood is sufficiently allowed to settle and coagulate before centrifugation. If centrifugation is performed before the blood is completely settled and coagulated, the blood clot may not contract completely, and the fibrin network may not be fully formed. At this time, centrifugal force may not be able to effectively penetrate and isolate the serum and blood clot. The result is often manifested as abnormal position of the separation gel layer, suspended fibrin fibers or small clots in the serum. These residual substances may interfere with the subsequent sampling process of automated instruments and potentially affect the accuracy of some detection items.

3, The Dual Effect of Centrifugal Environment Temperature

The ambient temperature during centrifugation has a significant impact on the physical state and separation efficiency of the separation gel. When the temperature is low, the viscosity of the separation gel may increase and the flowability may decrease, affecting its flipping and positioning during centrifugation; When the temperature is too high, especially when it exceeds the storage temperature range specified by the product, it may cause some components in the separation gel to dissolve or the stability to decrease, and even dissolve in trace amounts in the serum. This dissolved substance may form visible oil droplet like suspensions, which may not only block the instrument sampling needle and reaction cup, but also cause chemical interference to certain biochemical tests.

4, Standard setting of centrifugal operation parameters

Centrifugation is the core step that promotes the formation of an effective isolation layer in the separation gel. The standardized operation requires that after blood collection, gently invert and mix the coagulant to ensure full contact with the blood. Then, stand upright for a sufficient amount of time until the blood is completely coagulated before centrifugation. Horizontal rotors should be used during centrifugation, and centrifugal force and time should be strictly controlled. When the centrifugal force is insufficient, it is not enough to drive the separation gel to completely move between the serum and the cell layer, which may lead to incomplete isolation; Excessive centrifugal force or prolonged time may damage the network structure of the separation gel, causing it to lose its thixotropy, and even leading to colloidal dispersion or abnormal compression of the cell layer, which also affects the separation quality.

5, Potential changes in serum physical properties

The main physical factor determining whether the separation gel can be stably suspended between serum and cells is the density of the serum, not its viscosity. In pathological or physiological conditions, such as hyperlipidemia, hyperproteinemia, or certain metabolic diseases, serum density may significantly increase. When the serum density approaches or exceeds the separation gel density, it weakens the net buoyancy acting on the colloid during centrifugation, resulting in incomplete flipping or unstable retention of the separation gel at the interface position, leading to incomplete floating or settling of the separation gel layer.

In summary, to achieve an ideal serum separation effect, it is necessary to comprehensively consider multiple factors such as the quality of the separation gel product, the integrity of the specimen coagulation, the temperature of the centrifugation environment, standardized centrifugation operations, and the physical properties of the patient's serum itself. Inspectors should follow the product manual specifications during the operation process and pay attention to observing abnormal specimens. By optimizing the pre-processing process, sample quality can be guaranteed to the greatest extent possible, laying the foundation for the reliability of subsequent testing results.

Hubei Xindesheng Material Technology Co., Ltd. specializes in the production of blood collection tube additives such as serum separation gel. With nearly 20 years of research history in serum separation gel, we have unique insights into controlling the specific gravity of separators. Therefore, we also provide high-quality PRP gel to our customers. If you are interested in this product, please click on the official website for more details or contact me!