Where does the blood come from for determining the blood type and Rh factor, the rules

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Blood test

Blood is a fluid that circulates through the human body. Currently, it is classified by the fact of the presence or absence of antigens that are contained on the surface of red blood cells.

In 1900, the scientist Landsteiner discovered four blood groups. At the present time, there are many classifications, but the most common is the division into groups and Rh. The group is inherited from parents to the child and does not change during life.

Classification of blood

In addition to the differences in the groups, the blood is divided into two types according to the Rh Rh-factor. 85% of the total population of the Earth has a positive and only 15% is negative.

But where do the blood come from to determine blood type and Rh factor? Why do you need to know these characteristics of an ordinary person? The answers to these questions are simple.

Determination of Rh factor


  • The importance of the group and Rh factor
  • Where is the biomaterial taken from?
  • Pregnancy Analysis
  • How is the study going?

The importance of the group and Rh factor

Knowledge of the characteristics is necessary if there is a risk of hemorrhage. Restock the body with this problem can only donor material. And in this case, the group and the Rh factor are important, because:

  • If the characteristics of the patient's blood and donor blood do not coincide, rejection and death occurs.
  • Incompatibility of Rhesus factors is deadly, even if there is a transfusion from group to group.

Doctors can determine these indicators even under extreme conditions, but this will be a waste of time.

Knowledge of the characteristics is important for transfusion, for preparation for organ transplantation, for operations, for pregnant women.

Where is the biomaterial taken from?

Patients ask: where do they get blood for the blood group and the Rh factor? The answer is simple: if a person is an adult, the fence is carried out from the vein, since the venous carries more information and contributes to the accuracy of the results.

Before a fence it is important to follow the rules:

  • You can not eat before the test.
  • To go through the procedure in the morning.
  • Several weeks before the procedure, stop taking medication. If discontinuation of medication is not recommended, notify the doctor who is taking the fence, what substances, at what dosage and for what time do you take.
  • A few days before the analysis, limit alcohol consumption and quit smoking.
  • Two days before the procedure to minimize physical stress and stress.
  • The day before the test, you can not eat fatty and fried.
To ensure an accurate result, quit smoking and spirits

To find out the blood group and where the blood is taken from, you should contact the polyclinic where the analysis will be performed. But most often an analysis of venous fluid.

To take blood for analysis on the blood group of a newborn baby can be from the heel or thumb. To determine the Rh factor and group, plasma, platelets and red blood cells are removed by centrifugation.

Pregnancy Analysis

One of the important indicators that should be paid attention when planning pregnancy, is the compatibility of the characteristics of the biomaterial of the parents, and whether there are any differences in their Rh. It is important, because the:

  • If Rhesus factors are incompatible in parents and the child, Rh, opposite to the mother, can get out, which will cause Rh-conflict.
  • Differences in the characteristics of the blood of the spouses will cause infertility in women.

Before conception, the analysis is recommended to go to both parents. Rhesus-conflict may not manifest itself, and the newborn will see the world without problems, but it is not recommended to take risks.

But, what if the need for analysis arose in the course of pregnancy, where do bloods from the Rh factor and the group from pregnant women come from? The norm of the fence is the same: from the vein.

In this case, it is important to check whether the mother and the fetus match the characteristics of the biomaterial. In the early lines, the protein from the baby's erythrocytes tries to get into the mother's blood and, if they are observed discrepancy in terms of Rh, there is a process of rejecting the mother's mother of her child - rhesus-conflict.

How is the study going?

In the laboratory, an analysis is carried out using a test reagent-an antirezus serum. The process is simple and consists of several stages:

  • The blood is mixed with the polyglucin solution and placed in a test tube.
  • After this, blood is added to the test tube and gently mixed.
  • The tube is placed in a centrifuge for a while.
  • After centrifugation, a visual assessment of the results is carried out: if sediment is observed, saline is added to the tube.
  • If flocculation occurs, and the liquid becomes white, Rhesus is positive. If the liquid is pale pink, Rh is negative.

The process is fast and does not take much time, but the benefits are considerable.


The procedure of the analysis is simple, and at the present level of development of medicine it is safe. The answer to the question: where do they take blood from the Rh factor and the group, should not be frightened. Taking a biomaterial from a vein is not dangerous, it is a standard procedure that will be important in transfusion or if you decide to have a baby.

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