JPS6129669B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for separating blood collected in a container into serum or plasma and blood cells by centrifugation.

In recent years, testing of blood components in clinical laboratory departments has become extremely important, and the number of tests conducted has continued to increase. Among these, many serological tests use only serum or plasma as a sample, and it is necessary to separate serum or plasma from blood cells as a pre-test procedure. For this reason,
Conventionally, serum or plasma has been collected by centrifuging to precipitate blood cells and then sucking it up in a bivet. However, this method provides insufficient separation and is very time-consuming, and recently various methods have been devised to allow serum or plasma to be collected easily and with high yield. One method is to add a substance having a specific gravity intermediate between that of serum or plasma and blood cells to a blood sample, and use centrifugation to position the substance between the two to form a separation wall. According to this method, it is possible to separate serum or plasma only by decantation,
Although it is possible to reduce time and labor, it also has the following drawbacks.

That is, typical methods include a method using styrene beads as a serum or plasma separation material;
A method using a thixotropic composition consisting of a mixture of silicone and silica is known, but the former consists of styrene beads that are formed when an unexpected force is applied, such as by an impact, after separation is completed. This method has the disadvantage that the separation wall is destroyed, making it impossible to transport test tubes for blood collection, etc. Furthermore, since the separation wall is an aggregate of powder and is not a continuous structure, blood cells may be mixed into serum or plasma. It also had the disadvantage of low equi-separation accuracy. Although the latter is generally superior to the former in terms of transportation, fractionation, and separation performance, because the separation material has thixotropic properties, it takes time to show good fluidity due to centrifugal force. Depending on the separation conditions, the separation wall may not be formed sufficiently uniformly, resulting in poor separation, and on the other hand, dispensing a fixed amount into a container such as a Spitz tube may be difficult, resulting in poor work efficiency. In addition, air bubbles generated when air is drawn in during these operations are difficult to eliminate during the vacuuming process of the vacuum blood collection tube, reducing the degree of vacuum in the blood collection tube and causing variations. , Blood collection performance tends to deteriorate.Furthermore, from a component standpoint, the amount of silicone oil sufficient for separation and the amount of silica that can provide a high degree of thixotropy are important because silicone oil slows down the blood coagulation rate and shortens test time. However, the silica adsorbs the components to be tested in the blood, impairing the accuracy of the test.Furthermore, these raw materials are extremely expensive, reducing their industrial value.

The present invention overcomes the drawbacks of the prior art as described above,
The present invention provides a new method for separating serum or plasma from blood with high efficiency and high concentration.The gist of the method is to separate blood collected in a container into serum or plasma and blood cells by centrifugation. In the method, chlorinated polybutene has a specific gravity of 1.026 to 1.09 and has fluidity when at rest, but has poor compatibility with liquid silicone, and chlorinated polybutene has a specific gravity of 1.026 to 1.09 and is smaller than the above chlorinated polybutene and has no fluidity when at rest. However, it exhibits thixotropic properties. A method for separating serum or plasma, characterized in that a mixture of liquid silicone and a gel composition comprising a thixotropic agent is allowed to coexist with blood in a container, and then centrifuged.

The chlorinated polybutene used in the present invention is
It is a liquid substance with a specific gravity of 1.026 to 1.09, preferably 1.03 to 1.08, and is fluid at rest, and a viscosity of 500 to 2,000,000 CPS at 25°C, especially 1,000 to 1,000.
1000000CPS is preferred. The chlorinated polybutene has poor compatibility with liquid silicone.

The gel composition used in the present invention has a specific gravity of 1.026 to 1.09, preferably 1.03 to 1.08, which is lower than that of the above-mentioned chlorinated polybutene, and has thixotropic properties although no flowability is observed at rest. It is composed of liquid silicone and a thixotropic agent. Examples of the thixotropic agent include powdery materials such as silica, alumina, talc, bentonite, titania, zirconium, asbestos, and carbon black.
The gel composition is prepared by adding the above-mentioned thixotropy imparting agent to a liquid silicone such as dimethylpolysiloxane, mixing the mixture, and adjusting the specific gravity depending on the amount added and the like. Note that when using a thixotropic agent, it is important to ensure that it is uniformly dispersed when mixed into liquid silicone, and that subsequent operations, such as mixing with a viscous liquid, filling (dispensing) into containers, and centrifugation operations, are important. During the process, the silicone should not be released from the liquid silicone, and the dispersion state should not become non-uniform.

When the chlorinated polybutene and the gel composition are used to separate serum or plasma, they are mixed to form a mixed state. They are not in a compatible state at all, and due to the difference in specific gravity between the two by centrifugation, they eventually form a separation wall in which the former is in the lower layer and the latter is in the upper layer. That is, the chlorinated polybutene and the above-mentioned gel composition appear to be mixed uniformly at the beginning of the centrifugation operation, but as the centrifugation operation progresses, there is a difference in specific gravity and poor compatibility between the two. Therefore, the separation wall is finally composed of two layers, the upper part of which is made of the above-mentioned gel composition and the lower part of which is made of chlorinated polybutene, and this is where the elements that exhibit many of the functions and effects of the present invention are present.

Here, when the two are in a mixed state, the above-mentioned gel composition divided into small pieces is uniformly dispersed in the chlorinated polybutene, and preferably in this state, blood collected in advance in a container is By centrifugation, the particles of the gel-like composition gradually rise through the chlorinated polybutene, and the particles eventually connect with each other and become integrated, covering the entire top surface of the chlorinated polybutene layer. As a result, after the centrifugation operation is completed, a layer made of the gel-like composition that does not exhibit fluidity is formed as an upper layer of the separation wall, and blood cells are located below the separation wall, and blood cells are located above the separation wall. Serum or plasma is located here.

To summarize the noteworthy points of the present invention, while maintaining the effects of the conventional method of separating serum or plasma using chlorinated polybutene or a gel composition alone, the present invention can combine both compositions. It can be said that the problems of the conventional method have been successfully solved by cleverly combining and arranging them as explained in .

The serum or plasma separation method of the present invention has a specific gravity of 1.026.
~1.09 and has fluidity when at rest, but has poor compatibility with liquid silicone; and liquid silicone, which has a specific gravity of 1.026 to 1.09 and is smaller than the above chlorinated polybutene, has no fluidity when at rest, but exhibits thixotropic properties. Since a mixture of a gel-like composition consisting of a thixotropic agent and a thixotropic agent is allowed to coexist with blood in a container, a centrifugation operation is performed.
First of all, the first effect is that the mixture of the chlorinated polybutene and the gel composition as described above has good fluidity, and a gel composition with excellent thixotropy can be obtained. Problems that can be observed when used alone, such as the need for time to show sufficient fluidity, the tendency to form bubbles and difficulty in defoaming, and low dispensing accuracy and poor work efficiency, etc. Not only can this be solved, but the amount of gel composition used can be reduced, so it is possible to avoid the delay in blood coagulation that occurs when there is a large amount of silicone, and furthermore, the deterioration in test accuracy that occurs when there is a large amount of silica. For example, cost can be improved by reducing the amount of liquid silicone used.

The second effect is that after the centrifugation operation is completed, the separation wall and the upper layer are formed from the above-mentioned gel-like composition that does not exhibit fluidity when it is stationary. For example, the separation wall that has been formed is easily destroyed when an unexpected force is applied due to an impact after separation, it is difficult to smoothly separate serum or plasma by decantation, and there are also problems with pipettes. Even when using the suction method, chlorinated polybutene may adhere to the tip of the pipette, staining the tip of the pipette, clogging the inside of the pipette, and even causing stringiness when pulling up the pipette, causing damage to Spitz tubes, etc. It is possible to solve problems such as soiling the container or contamination with serum or plasma, and also the disadvantages of using styrene beads as a serum or plasma separation agent.
For example, problems such as the tendency of the separation wall to be destroyed and the tendency for bead particles to be released from the separation wall and mixed into serum or plasma can be solved in the same manner as described above.

Next, examples of the present invention will be shown.

(Example) Chlorinated polybutene with a specific gravity of 1.08 and a viscosity of 100,000 CPS at 25°C was prepared, and as a gel composition, a silicone fluid (dimethylpolysiloxane with a specific gravity of 0.97, "L-
45) Silica powder (amorphous hydrophobic silica fine powder with a specific gravity of 2.30, "Aerosil R972" manufactured by Degussa, USA)
By adding and sufficiently kneading, a composition having a specific gravity of 1.05 and having excellent thixotropic properties was prepared.

Next, the above two compositions were mixed and stirred at a volume ratio of 3 parts of the chlorinated polybutene to 1 part of the gel composition, and a total amount of 2 c.c. A centrifugation operation was performed at 2500 rpm for 10 minutes while the cells were added to the solution and allowed to coexist. After the centrifugation operation, inside the Spitz tube,
Serum, gel composition, chlorinated polybutene, and blood clot are separated into layers from the top in this order, and a separation wall made of the gel composition that does not flow in a static state is formed, so serum collection is as follows: It was confirmed that not only the method of sucking up with a pipette but also the method of decantation can be carried out extremely smoothly and accurately with sufficient yield.

Claims (1)

[Claims] 1. A method for separating blood collected in a container into serum or plasma and blood cells by centrifugation, which has a specific gravity of 1.026 to 1.09 and has fluidity when at rest, but is in a liquid state. A gel-like composition consisting of chlorinated polybutene, which has poor compatibility with silicone, liquid silicone, which has a specific gravity of 1.026 to 1.09 and is smaller than the above chlorinated polybutene, and exhibits thixotropic properties although it has no fluidity at rest, and a thixotropic agent. 1. A method for separating serum or plasma, which comprises performing a centrifugal separation operation while coexisting with blood in a container. 2. The separation method according to claim 1, wherein the gel composition is a silicone fluid with silica powder added thereto. 3 The viscosity of chlorinated polybutene at 25℃ is 500
20,000,000 CPS. The separation method according to claim 1 or 2.