Albumin: Composition, Properties, and Dosage Forms
Albumin solution is a key protein preparation produced using the plasma fractionation method. In the finished medicinal product, purified albumin accounts for 97% of the total protein content.
The preparation is available in several concentration options, which determine the active substance content:
- 5% solution (contains 5 g of protein per 100 ml);
- 10% solution (includes 10 g of protein per 100 ml);
- 20% solution (highly concentrated, 20 g per 100 ml).
The solutions are packaged in vials of 50, 100, 250, and 500 ml. A critical stage of production is heat treatment. To completely eliminate the risk of transmitting serum hepatitis to the patient, the preparation undergoes prolonged pasteurization—heating at 60 °C for 10 hours.
The main pharmacodynamic property of the preparation is its pronounced oncotic effect. Entering the vascular bed, protein molecules actively retain water, leading to a rapid increase in circulating blood volume (CBV). This specific physiological mechanism provides albumin's powerful anti-shock effect.
Rules of Administration and Dosing of Albumin
The administration of the preparation requires strict justifications. The main laboratory criterion for initiating therapy is a drop in the patient's own blood albumin level below 25 g/L.
Main indications for transfusion:
- Various types of shock conditions and burn disease;
- Hypoproteinemia and hypoalbuminemia (including against the background of tumor growth or severe purulent-inflammatory processes);
- Replenishing losses during plasmapheresis;
- Use in combination with whole blood or red blood cell transfusion in massive blood loss and posthemorrhagic anemia.
A relative contraindication to administration is severe allergic diseases in the patient.
Dosing regimen directly depends on the concentration of the chosen solution:
- 20% solution: administered in a volume of 100–200 ml;
- 10% solution: administered in a volume of 200–300 ml;
- 5% solution: requires volumes of 300–500 ml or more.
Standardly, the preparation is administered intravenously by drip at a rate of 40 to 60 drops per minute. However, in the rapid development of shock, bolus administration is permitted for emergency restoration of CBV. Before starting a full infusion, the physician is obliged to perform a biological test.
Protein Preparation: Features and Differences
Unlike highly purified albumin, the preparation called "Protein" is an isotonic solution containing stable pasteurized human plasma proteins at a concentration of 4.3–4.8%. The total protein content in such a solution ranges from 40 to 50 g/L.
Component composition of protein:
- Albumin — accounts for 75% to 80% of the total protein mass;
- Stable $\alpha$- and $\beta$-globulins — make up the remaining 20–25%.
In its properties, this combined solution is as close as possible to native blood plasma. It is available in 250–500 ml vials.
Indications for its use are similar to those for regular plasma transfusion. However, there is a strict rule: protein administration must necessarily be combined with a transfusion of donor blood or red blood cell mass.
Dosing regimens:
- For the treatment of hypoproteinemia: 250–500 ml per day (the course lasts several days);
- In severe shock and massive blood loss: the infusion volume is increased up to 1500–2000 ml.
As with albumin, the preparation is administered predominantly by drip, and in severe shock or critically low blood pressure — by the bolus method.
Antigenic Structure of Plasma Proteins
When working with blood protein preparations, their complex antigenic nature must be taken into account. It has been proven that more than 200 different antigens are located on the surface of plasma protein molecules.
Immunologically, these antigens do not exist chaotically — they are grouped into 10 major complexes (among which Ym, Hp, Yc, Tf systems, and others are distinguished). This structural diversity once again emphasizes the absolute necessity of performing a biological test before starting the transfusion of any protein fractions.
Briefly: answers to topical questions
What are the absolute and relative contraindications to albumin administration?
A relative contraindication to albumin administration is severe allergic diseases. There is no information on absolute contraindications, however, a critical condition for the immediate discontinuation of the preparation is the development of pulmonary edema. Patients with allergic pathologies (bronchial asthma, drug dermatitis) constitute a risk group for developing anaphylactic shock when using protein plasma substitutes.
How is the biological test technically performed before protein preparation transfusion?
The biological test before protein preparation transfusion is performed according to a standard three-step method with intermittent administration.
The execution technique includes the following stages:
- First administration — 5 ml of the preparation is transfused.
- Second administration — after 3 minutes, 10 ml is transfused.
- Third administration — after another 3 minutes, 15 ml is transfused.
In the intervals, the patient's condition is assessed. If there are no signs of a reaction (anxiety, tachycardia, labored breathing, facial flushing, itching, rash, drop in blood pressure), the transfusion is continued.
What antigenic systems of plasma proteins are distinguished in immunology?
In immunology, 10 complexes of plasma protein antigenic systems are distinguished. More than 200 antigens have been detected on the surface of protein molecules, which are grouped into these categories.
Among them, the following complexes are distinguished:
- Ym — plasma antigenic system.
- Hp — plasma antigenic system.
- Yc — plasma antigenic system.
- Tf — plasma antigenic system.
Unlike cellular antigenic systems, plasma systems have no practical significance in clinical transfusiology.
What complications can occur during blood protein preparation transfusion?
Allergic, respiratory, and pyrogenic complications may develop during the transfusion of blood protein preparations.
Main types of complications:
- Anaphylactic shock is a severe allergic reaction that occurs upon the administration of protein blood substitutes (patients with bronchial asthma or drug-induced dermatitis are at risk).
- Pulmonary edema is a respiratory complication, the risk of which increases significantly when human albumin is co-administered with vasopressors.
- Pyrogenic reactions present with fever and chills toward the end of or after the transfusion.
To prevent complications, the administration rate of protein preparations should be 20–40 drops per minute.
To memorize albumin dosages, use the "inverse proportion" rule: the HIGHER the percentage concentration of the solution (20% → 10% → 5%), the LOWER the required volume of administration (100–200 ml → 200–300 ml → 300–500 ml).
Class and exam questions
How is hepatitis transmission prevented during the production of blood protein preparations?
All solutions undergo mandatory prolonged pasteurization — they are heated to 60 °C and kept at this temperature for exactly 10 hours, which reliably rules out the transmission of the serum hepatitis virus.
Can albumin and protein solutions be administered as a bolus injection?
As a general rule, preparations are administered intravenously by drip infusion (40–60 drops per minute). However, in severe shock or a critical drop in blood pressure, emergency bolus administration is permitted.
How does the composition of the "Protein" preparation differ from albumin solutions?
Protein solution is a complex preparation. It contains not only albumin (75–80%), but also stable $\alpha$- and $\beta$-globulins (20–25%), making its properties as close as possible to whole human plasma.
What else to study on this topic
- Blood plasma fractionation technology
- Rules and algorithm for performing the biological test prior to transfusion
- Pathophysiology of oncotic pressure and water redistribution in the body
- Detailed characteristics of plasma antigenic complexes (Ym, Hp, Yc, Tf)
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