IE50323B1 - Blood collecting tube - Google Patents

Description

The present invention relates to a bloodcollecting tube containing a blood-coagulation promoting medium.

Serum can be separated from whole blood by mixing 5 the blood with a blood-coagulation promoting medium and a serum separating agent, and then centrifuging the mixture. The serum separating agent forms a layer separating the serum from the other blood components. This is described in Patent Specification No.S032?2j from which the present Application is divided and to which reference should be made for full details.

The present invention relates to a bloodcollecting tube in which a blood-coagulation promoting medium is disposed, which tube is particularly (but not exclusively) useful with a serum separating agent as described in the abovementioned Patent.

According to the present invention, there is provided a blood-collecting tube containing therein a blood coagulation-promoting medium,which medium comprises a carrier having a specific gravity higher than that of blood cells, and a powdered blood-coagulation-promoting agent supported on the carrier, and is held between the inner walls of the blood collecting tube in an intermediate portion of the tube.

A blood-collecting tube of the invention may also contain a thixotropic serum separating agent therein at the bottom.

In order that the invention may be more fully understood, an embodiment thereof and its use ’will now - 3 be described, by way of example only, with reference to the accompanying drawing, wherein: FIGURE 1 ie a perspective view of a bloodcollecting tube ready for use; and FIGURE 2 is a sectional view of the blood tube of Figure 1 after addition of the blood sample and centrifugal separation.

As shown in Figure 1, about 1.7 ml of a liquid separating agent composition 1 (as described in Patent Specification No. 5032>2> )was put in the bottom of a 10 cc tube 2. A polyester unwoven cloth 3 coated with 1 - 5 mg of diatomaceous earth (e.g. Caper Flattery Sand, trade name WG-200, for Kyoritsu Ceramic Materials Co., Ltd.) or micro-glass powder, was then placed at a slant in the tube. The diatomaceous earth or micro-glass powder acts ae a blood-coagulation promoting agent and is supported on the cloth 3 which serves principally as a carrier. The tube was then stopped with a butyl rubber plug 4, the interior of the tube being under reduced pressure. A blood sample was then placed in the tube and allowed to stand for 7 to 8 minutes. As a result, the diatomaceous earth became dispersed in the blood upon the introduction of the blood, and it accelerated blood coagulation together with the nonwoven cloth 3. Adequate coagulation was then attained within this short time. The tube was then placed in a centrifuge for 10 minutes at 700 1,000 g, and the liquid separating agent composition became stably distributed between the serum and the clot layers. This state is shown in Figure 2. Because the liquid separating agent is thixotropic and has a specific gravity between that of the blood serum 5 and that of the blood clots 6, it stays between the blood serum 5 and the blood clot 6, forming a gel that separates these two layers. Since the diatomaceous earth and the unwoven cloth 3 have higher specific gravities, they are not in the layer of blood serum 5. Thus, the blood serum 5 obtained was of high purity with no entrainment of fibrin. This blood eerum 5 was readily collected from the blood S0323 - 4 collecting tube by decantation or by suction through a fine nozzle.

Methods for manufacturing the blood-coagulation promoting medium such as non-woven cloth fixed with a prescribed amount of blood coagulation promoting agent may be easily carried out by a dipping method and the like.

In the above example, a serum-separating agent is preliminarily introduced into the tube. However, this invention is not limited to this procedure. For example, the serum-separating agent may be provided together with its container at an upper portion of a blood sampling tube after the sampling of blood and removal of the rubber cap. In this case, the serum-separating agent is introduced from the container into the blood-sampling tube by a centrifuging operation and forms a seal at the interface between the serum portion and the clot portion.

When a tube of the invention is used as a serum separator with a liquid separating agent of our said copending Patent Application, the agent does not fora water-repellent film in the blood collecting tube by releasing water-repellent substances and consequently does not cause delay of blood coagulation. Because the blood collecting tube is made of glass, it accelerates coagulation when contacting blood at the surface, so that it is necessary to keep the inner surface clean.

Accordingly, compared with conventional liquid separating agents which have the drawback of forming water-repellent film, the time needed for collecting blood serum using an agent of our said copending Application in a tube of the present invention, is shortened, most especially with the use of diatomaceous earth and unwoven cloth. The time saving can amount to as much as 30 minutes.

When encapsulation in a blood collecting tube is performed, sterilization is desirable. In clinical tests, no chemical or physical changes that cause adverse effects were found after applying gamma-ray sterilization a dose of 2.5 megarad.

Claims (7)

1. A blood-collecting tube containing therein a blood coagulation-promoting medium, which medium comprises a carrier having a specific gravity higher than that of 5 blood cells, and a powdered blood coagulation-promoting agent supported on the carrier, and is held between the inner walls of the blood collecting tube in an intermediate portion of the tube.

2. A blood-collecting tube according to claim 1, 10 wherein said blood coagulation-promoting agent is selected from glass, kaolin, bentonite and diatomaceous earth.

3. A blood-collecting tube according to claim 1 or 2, wherein said powdered blood coagulation-promoting agent comprises diatomaceous earth. 15

4. A blood-collecting tube according to any preceding claim, wherein said carrier comprises a polyester unwoven cloth.

5. A blood collecting tube according to any preceding claim wherein said blood coagulation-promoting medium is 20 disposed at the middle of the blood-collecting tube.

6. A blood-collecting tube according to any preceding claim, wherein the tube has a thixotropic serum separating agent therein at the bottom.

7. A blood-collecting tube according to claim 1, 25 substantially as hereinbefore described with particular reference to and as illustrated in the accompanying drawings. Dated this the 3rd day of October F.R. KELLY & CO., 1985. By: Executive. - j 27, Clyde Road, Ballsbridge, Dublin AGENTS FOR THE APPLICANTS. TERUMO CORPORATION 1 Sheet FIG.1. FIG.2.