When preparing for blood transfusion, a test for individual compatibility is a prerequisite. As a rule, there are two reactions: a test according to the ABO system and a Rhesus factor. To determine the reaction, the recipient must take blood from a vein, after which it is broken down into a clot and serum.
Types of reactions
There are two main types of reactions:
- The test carried out according to the ABO system consists in dropping a drop of blood serum directly from the recipient himself onto a completely clean surface, after which a small drop of donor blood is applied from a special bottle. Two types of blood are mixed together. A test for individual blood compatibility, which is carried out in this way, should be carried out at a temperature not exceeding 25 degrees, and the results can be obtained in just five minutes.Experts believe that if there is no agglutination of red blood cells, then the blood is compatible with the donor. This method helps to quickly navigate and make a timely blood transfusion, which may well save a person’s life.
- Conducting a test for individual compatibility by Rhesus factor must be carried out only after a test according to the ABO system. There are two methods for performing a Rhesus factor test: a test in which 33% polyglucin must be used; sample using 10% gelatin.
What is the essence of the Rh factor test using polyglucin?
Specialists most often use a test with polyglucin. As a rule, the reaction is studied in a special test tube without heating, and the results can be obtained faster than in five minutes. The test is as follows:
- Two drops of recipient blood and one drop of donor blood are placed at the bottom of the tube.
- Polyglucin solution is carefully added to the contents of the tube.
- Everything is thoroughly mixed, for this it is enough to tilt the tube, rotating it around its axis.
- It is important to remember that the tube must rotate for 5 minutes, then physiological saline is added and everything is mixed again.
Evaluation of the results is carried out due to the presence of red blood cell agglutination, if a reaction is present, then the blood is incompatible, naturally, such blood should not be transfused. If uniform staining occurs in the test tube, this indicates compatibility.
Gelatin Sample
A test for individual compatibility using gelatin is carried out as follows:
- At the bottom of the medical tube, one drop of donor's separated red blood cells is placed, which must first be washed at least ten times using saline.
- After this, 2 drops of gelatin heated to a liquid state are added, in a 10% ratio, and two drops of recipient blood.
- The contents of the entire tube are thoroughly mixed, and put on a steam bath, the temperature of which should be at least 48 degrees. Just ten minutes is enough to finally get the results.
- The next step will be the addition of 8 ml of saline. All content is mixed again and the result is evaluated.
If red blood cell agglutination is present, then such blood is not suitable for the recipient, in other cases it can be used.
How is a blood donor test done?
As soon as the blood group of the recipient is determined, donor blood should also be selected, it is desirable that it be single-group. The fact is that before transfusion, a test for individual group compatibility is mandatory. If the recipient has a Rhesus negative, then blood transfusion must also be negative.
Specialists, immediately before transfusion, must check the data of vials with canned blood. On each such ampoule, the date of collection, the number in the operational journal, the name of the institution and information about the donor are indicated. The blood group is necessarily marked, for example, the blue color belongs to the second group, red to the third, yellow is the fourth blood group.
When the blood settles, it has a transparent yellowish layer called plasma, dark red erythrocytes accumulate at the bottom. Suitable donated blood does not have any clots, films and flakes.
Blood transfusion preparation
In addition to taking an individual compatibility test, there are certain transfusion rules. In no case should you transfuse cold blood, it must be warmed for about an hour at room temperature. If it is urgently necessary to pour blood, then all manipulations are done immediately so that the patient's heart does not stop. It is important to remember that a blood transfusion is done at least an hour after a meal.
Before the start of blood transfusion, the blood group of the donor is necessarily indicated, and a blood group of the recipient is also checked. When using blood pre-prepared in vials, the metal cap first breaks off, and then the rubber stopper is treated with alcohol.
It is this cork that is pierced with thick needles, which can have different lengths. The transfusion system is connected to the short needle, and the long is connected to the catheter.
Why is a biological blood sample needed?
A biological test for individual compatibility is considered the final stage of preparation before the transfusion itself. As a rule, 15 ml of blood is poured, after which the patient is observed. If the patient does not have any symptoms, such as shortness of breath, abdominal pain and anxiety, then 10 ml of blood are again injected, and this operation is repeated three times. If there is no negative reaction, then the blood transfusion is completed to the end.
If the patient still complains about his condition, the blood transfusion stops, otherwise a blood transfusion shock may occur. Sometimes a blood transfusion is carried out to a patient under anesthesia, but then the pulse rate indicators are necessarily taken into account, blood pressure is measured.
The main complications of blood transfusion
In fact, there are a large number of complications, but the most dangerous is air embolism. It happens that the tests for the individual compatibility of the donor and the recipient are compatible, but the patient begins to develop complications. To prevent this from happening, a biological test is also considered mandatory. Donor blood is transfused gradually and with small interruptions, if the patient's condition does not change, then it is possible to transfuse blood to the end.
Recognizing that the blood is not suitable for the recipient is not so difficult, the patient may immediately have tachycardia, blood pressure rises, and there may be pain in the lower back and abdomen.
What happens after the blood is transfused?
As soon as the blood is no longer transfused, at least 5 ml is left in the vial and stored in the refrigerator for 2 days. Despite conducting tests for individual blood compatibility, one cannot be sure that complications will arise in any case, because they may not appear immediately, but with some delay. After the infusion, the patient needs to spend at least two hours in bed. Throughout the day, body temperature is constantly measured.
Conducting all necessary samples before blood transfusion plays an important role for the patient himself and if immediate and urgent action by doctors is not required, then all tests are considered mandatory, otherwise there is a risk of significant harm to the recipient's health.