Bilirubin is a chemical compound, one of the main components of bile produced by liver cells and taking part in digestive processes. It is a toxic pigment that is formed when the destroyed or damaged erythrocytes are components of the blood, and this occurs in the spleen. Further, bilirubin penetrates into the liver cells and turns into another, water-soluble form.
Fractions of bilirubin
Bilirubin in the human body and, in particular in the bloodstream, is represented by two kinds of fractions:
- Indirect (free) fraction , which is the bile pigment, insoluble in water and having the ability to pass through the cell membranes and disrupt their activity.
- Direct (bound) fraction , obtained by combining free bilirubin in hepatocytes and having water-soluble properties.
The sum of indirect and direct bilirubin in the bloodstream is a total (total) bilirubin, the determination of which is carried out during the biochemical study of venous blood. Let's consider, what norm or rate of the general bilirubin in a blood at women and about what analysis of the given indicator can tell.
The norm of total bilirubin in the blood
To determine the total bilirubin contained in the circulatory system, blood is taken from the ulnar vein in the morning time on an empty stomach. Various methods are used for the analysis. It should be taken into account that various factors influence the quality of the analysis. Thus, the results may be somewhat overestimated if before the study the patient took steroid preparations, erythromycin, phenobarbital, consumed food with a high content of carotenoids (carrots, apricots). Underestimated values can be determined by the fault of health workers who allowed a long standing of the material under study in the light, thereby causing oxidation of the serum.
The norm for women is the values of total bilirubin, fluctuating within 3.4 - 17.1 μmol / l (of which 80% falls on the indirect fraction). For men, the upper limit of normal values of this indicator is slightly higher. This fact is due to the fact that a smaller number of erythrocytes is produced in the female body. It should also be noted that during the period of gestation, especially in the last trimester, there may be a slight excess of the norm of the indicator in question, as a result of a violation of bile from the liver. However, after delivery, the value is normalized.
The diagnostic value of the indicator of total bilirubin
The concentration of total bilirubin in the blood stream gives important information about the quality of pigment metabolism in the body, the functional abilities of the organs participating in this exchange, allows physicians of various specialties to diagnose and evaluate the effectiveness of treatment of many diseases. Most often, this analysis is recommended for suspected liver pathology, hemolytic anemia. It should be understood that the indicator of the level of total bilirubin does not allow us to clearly determine the cause of its increase. Therefore, the study should be complemented by the study of fractions of bilirubin in the blood.
If during the analysis it is determined that an increase in total bilirubin is caused by an increased content of the indirect fraction, this may indicate:
- hemolytic anemia ;
- malaria;
- Gilbert's disease;
- the Kriegler-Nayar syndrome, etc.
When the total bilirubin is increased due to the bound fraction, one can suspect about:
- the Dabin-Johnson syndrome;
- hepatitis;
- cirrhosis;
- cholelithiasis, etc.
Exceeding the norms of both factions can tell about such pathologies as:
- liver cancer;
- alveococcosis of the liver;
- viral hepatitis, and others.
Reduction of total bilirubin in the blood is observed after large-scale blood loss of the body, against a background of general dystrophy.