METHODS FOR TESTING BLOOD TYPE

Field of the Invention

The present invention relates to blood test technologies. More particularly, the present invention relates to blood typing devices, and a method for testing blood type. Background of the Invention

Many industries related to blood, such as blood donation, blood transfusion, raw material inspection for blood derived products, etc., requires test on the relevant blood for special antibody or antigen. In many instances, it is required to know blood type (or blood group), which is related to the presence or absence of inherited antigenic substances on the surface of red blood cells (RBCs). For example, before a patient receives a blood transfusion, a number of laboratory tests must be performed on both the patient's blood and the incoming blood. A miss match between the incoming blood type and receiver's blood type may be fatal to the patient. Most commonly, blood group ABO and Anti-D in the Rh group are tested.

Hemagglutination, clumping of RBCs in the presence of antibody, is commonly used as the diagnostic method for blood type. However, it is tricky to differentiate agglutinated and un-agglutinated RBCs, especially for un-trained person with naked eyes. Many methods are therefore invented to help making the agglutination effects more visible to human beings.

Traditionally, blood typing or blood type testing is done manually. An operator mixes the antibody and the blood sample on a glass slide, waits for incubation, and watches the agglutination effect under a microscope. The authenticity of the test result will depend on the skillfulness of the test performer. Besides, the tedious process makes it impossible to meet the requirements of fast speed and large throughput.

U.S. Patent No. 5,512,432 discloses a method to make it easy to differentiate agglutinated and un-agglutinated RBCs with the help of an inert gel. Blood specimen of unknown blood type is placed in a reaction vessel filled with a mixture of the inert gel and antibody. The reaction vessel is then centrifuged. If the blood sample contains RBCs with the matching antigen, the antigen-antibody binding induced RBC complex will suspend on the upper surface of the inert gel. Otherwise, the complex will distribute in the middle of the inert gel or beneath it. The drawback of this method is two fold: the lengthy incubation time and the complicated centrifugation operation.

U.S. Patent No. 5,759,774 discloses another method using fully automated microplate. With the specially designed shape of the wells on the microplate, the agglutinated blood and un-agglutinated blood would have different visual patterns after incubation and mechanical shaking/centrifugation. Because of its standardized testing process and high throughput, blood banks tend to use the automated microplate as their standard blood typing method. On the other hand, because the incubation time is so long, many parallel test channels are required in order to meet the high throughput demand. Therefore, the complexity and the cost of the testing machine are high. Moreover, wash and recycle the used microplate may decrease the total efficiency of the lab.

Summary of the Invention There is a need for providing a good way for blood type testing. The present invention provides in an aspect a blood typing device, including: a sample hosting unit, adapted to host reaction between a sample of blood and substance associated with agglutination, host liquid for washing the sample of blood after the reaction, and presenting one or more visual signals to identify the type of the sample of blood; and a liquid absorbing unit contacted with the sample hosting unit, adapted to absorb the liquid from the sample hosting unit.

Further, the present invention provides in another aspect a blood typing device, including: at least one liquid transmissible membrane coated with substance associated with agglutination; wherein the liquid transmissible membrane has pores permitting single blood particles to go through while blocking agglutinated blood complexes.

Further, the present invention provides in another aspect a method for testing blood type, including: dropping a sample of blood onto the sample hosting unit of the blood typing device; dropping liquid for washing the sample of blood onto the sample hosting unit after the dropping of the sample of blood; and identifying the blood type of the sample according to one or more visual signals presented on the sample hosting unit after reaction between the sample of blood and the substance associated with agglutination.

Further, the present invention provides in another aspect a device for testing agglutinating, including: a sample hosting unit, adapted to host reaction between substance associated with agglutination and a sample, host liquid for washing the sample after the reaction, and presenting one or more visual signals to identify the occurrence of agglutination within the sample; and a liquid absorbing unit contacted with the sample hosting unit, adapted to absorb the liquid from the sample hosting unit. It can be seen that the present invention provides a fast and easy way for blood type testing.

Brief Description of Drawings

Figure 1, including Figures l(a)-(d), represents multiple contact relations between a sample hosting unit an a liquid absorbing unit;

Figure 2(a) and Figure 2(b) show a blood typing strip provided in an embodiment of the present invention;

Figure 3(a) and Figure 3(b) represent individual RBC movement of a blood sample after adding water to a sample pad;

Figure 3(c) and Figure 3(d) represent RBCs' aggregate movement of a blood sample after adding water to a sample pad;

Figure 4 represents a blood typing strip provided in another embodiment of the present invention.

In the above mentioned figures, there are sample hosting unit 10, liquid absorbing unit 11, sample pad 20, bibulous paper 21, substrate 22, blood sample 33, water drop 34, arm 40, bibulous paper 41, gap 43 and liquid adding part 44.

Detailed Description of the Invention

A blood typing device proposed in an embodiment of the present invention includes the following parts: a sample hosting unit 10 and a liquid absorbing unit 11 contacted with the sample hosting unit 10, wherein the liquid absorbing unit 11 can specifically be a bibulous paper.

The liquid absorbing unit 11 may contact with the sample hosting unit 10 at one end as shown in Figure 1(a), or at two ends of the sample hosting unit 10 as shown in Figure 1(b). Also, the sample hosting unit 10 may be all surrounded by the liquid absorbing unit 11 as shown in Figure 1(c) or partially surrounded by the liquid absorbing unit 11 as shown in Figure 1(d). One way to contact the liquid absorbing unit 11 with the sample hosting unit 10 is to have a portion of the two units overlapped and splice them together.

Furthermore, the blood typing device may be a strip further including a substrate for hosting the sample hosting unit 10 and the liquid absorbing unit 11. Also, the shape of the blood typing device is not limited to a strip, but can be a circle or any other shape.

Specifically, the sample hosting unit is a sample pad including porous material coated with substance associated with agglutination. In an embodiment of the present invention, the substance associated with agglutination is an antibody which is dry since dry antibody can be stored in room temperature, and it can be such as Anti-A or Anti-B or Anti-D. Alternatively, the substance associated with agglutination can be in a liquid form and dropped onto the porous material for performing a blood typing test, stead of previously coated on the porous material. It provides a more flexible way for blood typing test since it is not so easy to dry the substance associated with agglutination and coat it onto the porous material. Specifically, the porous material included in the sample pad is a hollow membrane, such as polyester membrane with pores. Also, the membrane can be such as a glass fiber membrane, a nitrocellulose membrane, or a cellulose acetate membrane. In an example, the pores are uniformly distributed on the membrane, thereby providing a better effort for showing visual signals to testers on the membrane after agglutination happens.

After dropping the blood to test on the sample pad, the antibody coated on the membrane resolves in the blood for follow up reaction. The polyester membrane hosts the reaction between the antibody and the antigen on the RBC surface. That is, the membrane provides a place to let the substance associated with agglutination reacts with the blood sample. If the antibody on the membrane and the antigen on RBC belong to the same blood group, the RBCs will agglutinate immediately. It should be pointed out that agglutination is the clumping of particles. In the presence of antibody (or other substance associated with agglutination), the antibodies (or other substance associated with agglutination) bind to multiple particles and join them, creating a large complex of particles. Agglutination is commonly used as a method of identifying specific antigens, and in turn, the identity of blood type. Because the clumping reaction occurs quickly and is easy to produce, agglutination is an important technique in diagnosis. The proposed blood type test is based on agglutination of RBCs in the presence of antibody, i.e., hemagglutination.

The average pore size of the membrane is approximately 50 micron with the smallest being 10-20 micron; the diameter of agglutinated RBC complex is usually larger than 100 micron; and the size of a single RBC is 10 micron or less. Thus, in the membrane soaked with liquid such as water, physiological saline, or phosphate buffered saline, individual RBCs can move smoothly through the pores of the membrane while agglutinated RBC complexes cannot. It should be pointed out that any liquid that will not affect agglutination reaction and/or biological property of blood can be used for washing the blood out of the sample hosting unit. In real application, the average pore size of the membrane can be designed according to requirements in order to permit individual RBCs to move through while block agglutinated RBC complexes. For example, the average pore size may fall within a range of 10 micron to 100 micron. If the sample of blood and the substance associated with agglutination have the same blood type, after the substance associated with agglutination resolves in the sample of blood, the substance associated with agglutination is able to clump single blood particles to create agglutinated blood complexes. Since the diameter of an agglutinated blood complex is larger than that of a single blood particle, a single blood particle is able to move through the membrane with multiple pores freely, while the movement of an agglutinated blood complex is limited due to the average size of the pores.

The bibulous paper in such as Figure 1(a) provides liquid flow control by unidirectional absorption of the water dropped on the polyester membrane. If agglutination happens, after adding water to the sample pad, because the RBC complexes is too large to pass through the pores of the polyester membrane with the water flow, the RBC complexes will stay in the polyester membrane indicating a red signal. If there is no agglutination, the RBCs will be washed away with water, leaving no color on the test pad. The existence of a specific antigen on RBC surface can therefore be determined from the leftover signal on the sample pad knowing the type of the antibody coated on the sample pad.

The substrate hosts the sample pad and bibulous paper and keeps them in tight contact. The bibulous paper at one end of the sample pad absorbs water dropped on the sample pad therefore guarantees the unidirectional movement of water in the polyester membrane. In this way, the water can be absorbed out of the sample pad rapidly and completely, which may increase the speed of blood typing test.

In some applications, the bibulous paper for absorbing water and the substrate for hosting both the sample pad and the bibulous paper can be optional.

Figure 2(a) and Figure 2(b) shows that a blood typing strip provided in an embodiment of the present invention includes three parts: sample pad 20, bibulous paper 21 and substrate 22. The sample pad 20 is coated with substance associated with agglutination and hosts the reaction between blood particles (such as RBC surface antigen) and the substance associated with agglutination. The substance associated with agglutination can be such as antibody, protein or inorganic salt, which can clump blood particles. Further, the top view of the strip is shown in such as Figure 1(a).

Figure 3(a) and Figure 3(c) represent different RBC or its aggregate movement of a blood sample 33 after adding water drop 34 to the sample pad 20. As shown in Figure 3(c) and Figure 3(d), if the RBC surface antigen matches the antibody coated on the test pad polyester membrane, the RBCs will form clump and stay in the polyester membrane, leaving obvious red color signal on the sample pad 20. Otherwise, the RBC will be washed away from the sample pad 20 and absorbed by the bibulous paper 21, leaving no visual signal on the sample pad 20. That is, when no agglutination happens, the procedure is as shown in Figure 3(a) and Figure 3(b).

Figure 4 represents a blood typing strip provided in another embodiment of the present invention, wherein the blood typing strip is able for testing multiple antigens within a single strip. Specifically, the sample pad has multiple arms 40 divided by gaps 43. That is, the multiple arms 40 are spaced apart from each other. These arms are coated with different antibodies. The gap 43 is used for isolating different arms and filled with nothing. As another choice, the gap 43 may be filled with colloid to better prevent liquid from flowing through the gap from one arm to another.

Multiple arms coated with different antibodies of multiple blood groups/families can be used in conjunction in order to obtain the complete blood group information of the blood sample. For example, two arms are set in an exemplary embodiment of the present invention, wherein these arms are coated with antibodies, such as Anti-A and Anti-B, respectively. Different combination of the arms with red signal left indicates the correct blood type of the sample. For another example, three arms coated with Anti-A, Anti-B and Anti-D are set. For yet another example, four arms are set while three of them are coated with Anti-A, Anti-B and Anti-D respectively and the fourth arm is coated with nothing.

Further, since there are separate arms on the sample pad, multiple droplets of blood sample need to be added to different arms. As these arms are connected at one end, water is only required to be added at a single location of the strip, which is called a liquid adding part 44. Accordingly, it is only required to add liquid for once to wash the blood sample out of all the arms.

In another embodiment of the present invention, a method for testing blood type is provided. The method includes: dropping a sample of blood onto the sample hosting unit of the blood typing device; dropping liquid for washing the sample of blood onto the sample hosting unit after dropping of the sample of blood; and identifying the blood type of the sample according to one or more visual signals, such as red signals, presented on the sample hosting unit after reaction between blood particles of the sample of blood and the substance associated with agglutination. In an example, the sample of blood and the liquid for washing the sample of blood are dropped onto the blood typing device from outside. The method provides a usage of the blood typing device as shown in Figures 1-4.

In an example, the method further includes: before dropping the liquid for washing the sample of blood, dropping the substance associated with agglutination onto the sample hosting unit. Since the substance associated with agglutination and the sample of blood are dropped onto the membrane with multiple pores of the sample hosting unit sequentially, the contact surface of the two materials is big enough to enable them to have a good reaction. Specifically, the substance associated with agglutination can be dropped before or after dropping of the sample of blood. The substance associated with agglutination that is dropped onto the sample hosting unit can be selected from the group consisting of antibody, protein, inorganic salt and red blood cell control solution. That is, the substance associated with agglutination can be antigen for reacting with corresponding antibody in serum of the sample.

Further, an embodiment of the present invention provides a device for testing agglutinating. The device for testing agglutinating includes: a sample hosting unit, adapted to host reaction between substance associated with agglutination and a sample, host liquid for washing the sample after the reaction, and presenting one or more visual signals to identify the occurrence of agglutination within the sample; and a liquid absorbing unit contacted with the sample hosting unit, adapted to absorb the liquid from the sample hosting unit. It can be seen that the sample hosting unit is adapted to hold the sample and the liquid for washing the sample, and further adapted to hold the substance associated with agglutination. Specifically, the device for testing agglutination can be a strip. After the existence of agglutination is found, the type of the sample can be determined accordingly since the type of the substance associated with agglutination is already known by testers. The sample can be something extracted from a testee or something after a further processing on things extracted from a testee. It should be pointed out that the sample is not limited to blood.

In an example, the sample hosting unit includes: at least one liquid transmissible membrane coated with the substance associated with agglutination; wherein the substance associated with agglutination is adapted to resolve in the sample dropped from outside, and clump single particles of the sample to create agglutinated complexes when the sample matches the substance associated with agglutination; and the liquid transmissible membrane has pores permitting the single particles to go through while blocking the agglutinated complexes after the liquid for washing the sample has been dropped from outside onto the liquid transmissible membrane.

Specifically, the sample can be blood, protein suspension or solution containing virus, such as hepatitis B virus, hepatitis C virus and human immunodeficiency virus. As to the sample that is achromatic, it is required to dye or color the sample. In this way, visual signals (such as red or blue signals) can be observed from the sample hosting unit after agglutination of the sample happens. To sum up, the present invention discloses a blood typing device and a blood type testing method by observing different visual signals associated with different levels of agglutination, which is caused by binding of antigen on the surface of RBC and antibody coated on the test pad. With cost-effective porous material such as polyester membrane or paper coated with antibody replacing the gel column or microplate, the invention eliminates incubation and centrifugation. In other words, this is a new device and method for accurate and rapid blood typing, which makes agglutination effect between antigen of blood and substance associated with agglutination such as antibody visible.

The present invention has at least one of the key differentiating advantages listed below.

1. Standardized process. There are only two simple steps to perform blood type test. Therefore, users do not need extensive training to perform the test accurately.

2. Fast test speed. The antibody is coated on the sample pad. Incubation time is not required for a reaction between blood particles and substance associated with agglutination, such as an antigen-antibody reaction. Therefore, the blood type test is rapid.

3. No centrifugation required. The sample pad will hold the agglutinated RBC complexes and represents red signal. No centrifugation is required in order to make the agglutination visible.

4. Low manufacturing cost.

5. Dry antibody is easy to preserve.

That is, this invention simplifies the process and increases the speed of the test by omitting the incubation and centrifugation process, which also results in reduction of the total cost. Therefore, the blood type test is accurate and fast.

The present invention discloses blood typing devices, and a method for testing blood type. The blood typing device includes: a sample hosting unit including substance associated with agglutination, adapted to host a sample of blood for dissolving the substance associated with agglutination, and host liquid for washing the sample of blood; and a liquid absorbing unit contacted with the sample hosting unit, adapted to absorb the liquid from the sample hosting unit. The present invention provides a fast and easy way for blood type testing.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.