Blood grouping and compatibility testing

General transfusion rules

According to current regulations, the recipient must be transfused exclusively with type-specific blood that is fully identical in the ABO, Rhesus, and Kell antigenic systems. The concept of the "universal donor" is considered outdated in modern practice and is no longer applied.

The only exception is made in emergency situations when the patient's blood type cannot be determined. In such cases, O-negative (ABO, Rhesus, and Kell) red blood cells may be used. A complete blood count is mandatory before transfusing cellular components (packed red blood cells, platelet concentrate).

Mandatory steps before transfusion

The physician has no right to rely solely on medical records and must personally verify the blood type of both the donor and the recipient.

After that, the individual compatibility test is performed:

• Two drops of recipient serum (fibrinogen-free plasma) and one drop of donor red blood cells are placed on a glass slide.
• If agglutination (clumping of red blood cells) is observed, the transfusion is strictly prohibited.
• The absence of agglutination allows proceeding to the next step.

The absence of a reaction on the slide does not guarantee complete safety in vivo due to differences in volume, temperature, and pH levels; therefore, a biological test is the next mandatory step.

Biological test and direct transfusion

The biological test is performed immediately before infusing the full volume of blood.

1. Approximately 10 ml of blood is injected into the patient over 3 minutes.
2. The transfusion is stopped, and the patient's condition is monitored for 3 minutes.
3. In case of incompatibility, a stress reaction occurs (changes in pulse, blood pressure, respiratory rate, fever, sweating).
4. This procedure is repeated twice more. The transfusion is continued only if there are no adverse reactions.

Direct blood transfusion is a direct transfusion from donor to recipient using a syringe method. This method is rarely used nowadays. Indications include hemophilia with persistent bleeding, clotting disorders (afibrinogenemia, acute fibrinolysis, thrombocytopenia), and stage III traumatic shock with blood loss exceeding 25–50% of BCC, if stored blood is ineffective.

For the first three syringes during a direct transfusion, a sodium citrate solution (2 ml of a 4% solution) is used to prevent clotting, and blood is injected slowly (one syringe every 2 minutes) — this serves as the biological test in this method.

Class and exam questions

What else to study on this topic

• Specifics of performing a direct transfusion (donor preparation)
• Indications for using various blood components
• Pathogenesis of the stress reaction during incompatible blood transfusion
• Causes of acute renal failure following transfusion

Other topics in the section "CHAPTER 6. BLOOD TRANSFUSION"

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.