Agglutination of blood is ... Blood groups and agglutination reactions

Agglutination of blood is the gluing and settling of red blood cells, bacteria and other cells that carry antigens.

The process occurs under the influence of agglutinins, which are specific substances. In the role of these substances act lectins or antibodies.

Possible types of agglutination when determining the blood type

Agglutination is specific and nonspecific. In the first case, the reaction occurs with the participation of three components:

• Antigens;
• Antibodies;
• Electrolytes (isotonic solution is used).

All possible types of agglutination are used in determining the blood group, but this is not the only case.

For what purpose is it used?

The blood agglutination reaction is used to identify the causative agent of an infectious disease. In this case, it settles, and it is easy to detect in the sediment. This process is used, as already mentioned above, and in determining the blood group. This is exactly what will be discussed later.

What are the features?

Erythrocytes contain type A and B antigens. They bind to antibodies ά and β, respectively. Blood groups and agglutination reactions:

• 1, 0 (ά, β) - there are no antigens on the surface of erythrocytes;
• 2, A (β) - antigen A and antibody β are present;
• 3, B (ά) - contains antigen B and antibody ;
• 4, AB (00) - there are two antigens, antibodies are absent.

It should be noted that antigens are already observed in the embryo. As for antibodies, they appear after birth, in the first month of life.

Compatibility of people depends on the blood group. This is the reason for the rejection of the fetus by the mother's body. In other words, it has antibodies to the blood antigens of the unborn child. In this case, incompatibility occurs. In addition, the blood group is necessarily taken into account in the transfusion.

Preparation

Blood groups and agglutination reactions are compatible concepts that are often used in medicine.

Before the test, it is important to follow certain instructions. It should be for a while to exclude the use of certain products and medicines. This will help make the results more accurate. Recommendations that need to be adhered to, the doctor appoints. The fact is that in different laboratories the ranges of the obtained values may not coincide, that is, they differ slightly.

Conditions for the test

To ensure that the blood group has been determined accurately, it is important to choose the right equipment. These include:

• Saline and pipette;
• Glass sticks;
• Standard isohemagglutinating sera;
• Dry earthenware plates, which are divided into 4 sectors.

There are also requirements for the test conditions:

• Daylight;
• The room temperature is above +16 ° C;
• Use of blood and serum volumes in a ratio of 1:10;
• Reliable results are obtained within 5 minutes.

The above are the main conditions and tools. Agglutination of blood can be carried out in several ways, and each of them puts forward individual requirements.

Methods

Possible methods for determining the blood group by agglutination:

• Standard method;
• Cross reaction;
• Use of tsoliklons;
• Express-method with application of the set "Erytrotest-groupcards".

Standard method

Blood agglutination is manifested with the use of red blood cells of the patient. Standard serums that contain known antigens are also used.

On a flat plate is placed on 1 drop of four serums. Then, with the help of glass sticks, the patient's blood is brought into it, which is to be examined. In this case it is convenient to use eye droppers. You should adhere to the ratio 1:10. Serum and blood are gently mixed. Within five minutes, you can evaluate.

Deciphering test results by a simple method

At the end of this time, clarification is observed in the drops of serum. In some, one can see that the agglutination of red blood cells occurred (small flakes), in others it is absent.

There are the following options:

• No reaction in all serum samples - group 1;
• Coagulation occurred everywhere, except for 2 samples - group 2;
• No reaction in only 3 samples - group 3;
• Agglutination occurred everywhere - group 4.

Thus, the main thing is to properly distribute serums. Then decipher the result is not difficult. If the agglutination of the blood is poor, it is recommended that the analysis be repeated. In the case of small flakes, they are examined under a microscope.

Cross-reaction

Sometimes, in a simple way, it is impossible to accurately determine a blood group. Agglutination in this case is carried out using the cross reaction method. Unlike the first variant of the test, standard red blood cells are of great importance here. The patient's blood is collected in a test tube, centrifuged, and then the serum is pumped out with a pipette for further research.

It in the amount of 2 drops is placed on a plate, then the standard red blood cells of groups A and B are added to it. The contents are mixed by shaking the container.

Results of the cross reaction method

After five minutes, the samples are ready for examination. The options are:

• Bonding occurred in both drops - group 1;
• Flakes are not observed in any of the samples - group 4;
• The process is visible in one sample - 2 or 3 group (depending on where the blood coagulated).

Method using tsoliklonov

To determine the blood group, agglutination in this way is carried out using synthetic substitutes for serums. They are called tsoliklonami. They contain artificial substitutes for ά and β-agglutinins, known as erythro tests (pink and blue, respectively). The reaction occurs between them and the red blood cells of the patient.

This method is the most accurate and reliable. Basically, it does not require a second study. Evaluation of the results is carried out in a similar way, as in the case of the standard method. The peculiarity is that the fourth blood group must necessarily be confirmed by reaction with a specific synthetic substitute (anti-AB). In addition, it does not show gluing when adding a solution of sodium chloride.

Express-method with a set of "Erytrotest-groupcards"

Considering possible methods of analysis in determining the blood group, it is worth noting that this method has its own characteristics. They consist in the fact that the result can be assessed not only in the laboratory, but also in the field. A special kit is used for the study. It includes a card with holes, at the bottom of which already there are dried reagents. In addition to anti-AB, anti-A and anti-B, anti-D is used, which makes it possible to determine the Rhesus factor.

This method does not require special preparation, it is allowed to use blood, which is taken from the finger, it is allowed the presence of preservatives in it. First, you need to drop a drop of water into each well to dissolve the ingredients. After that, blood is added, mixed slightly. After three minutes, the result will be obtained.

False agglutination

Sometimes the data obtained after the test is not true. This phenomenon depends on certain factors.

There are three types of false reactions:

1. Pseudoagglutination. True gluing does not happen, red blood cells simply fold in the form of coins. If you add a couple drops of saline, they break up. A similar phenomenon is recognized under a microscope.

2. Cold blood agglutination. Such a reaction is observed if the conditions for conducting the study were unfavorable. When the temperature is below +16 ° C, gluing can occur.

3. Panagglutination. If there is an infection in the blood, the test results may be false. This phenomenon is also possible in the case of cancer, in sepsis.

Agglutination is very important in medicine. It allows not only to determine the blood group, but also to identify the causative agent of diseases, as well as the presence of infections. The main thing is to follow the doctor's recommendations when preparing for this procedure. With regard to medical personnel, its task is to create an enabling environment and comply with all rules. Only in this way it is possible to achieve accurate results when performing blood agglutination.