One of the main stages in the diagnosis of diseases is a biochemical blood test, in which a number of indicators are determined, including the norm of bilirubin in the blood. Consider what kind of substance and how much it should be contained in the analysis of a healthy person.
What is bilirubin?
Bilirubin is one of the bile enzymes, which has a yellow-red color. It is formed as a result of the decomposition of blood components, in particular from hemoglobin, which secrete dead red blood cells during their injury (injury) or natural aging. Hemoglobin breaks down into heme and globin chains, which then turn into amino acids. And heme, interacting with enzymes, becomes indirect bilirubin, the norm of which is determined by the difference between total and direct bilirubin.
Indirectly called still unbound or free - it is toxic, as being fat-soluble, it easily penetrates into cells, disrupting their work. That is why the content of this fraction of bilirubin in blood above the norm is dangerous.
The enzyme in this form binds to blood albumins and enters the liver, where it undergoes "neutralization" and becomes water-soluble. This fraction is called indirect bilirubin. Such an enzyme is excreted with bile, but if the liver function is disrupted, the body ceases to cope with the task of converting indirect bilirubin into a direct, and its content in the blood becomes higher than normal.
Blood test for bilirubin
The amount of enzyme in the blood serum is determined in the biochemical analysis on a par with such indicators as hemoglobin, haptoglobin, cholesterol, urea, glucose, creatinine, triglycerides, and others.
Blood for research is taken only from the vein. On the eve of the analysis you can not drink juices, milk, coffee, sweet tea and alcohol. 8 to 12 hours before the delivery of blood can not be eaten, and the laboratory should come on an empty stomach. You can drink water.
The arm above the elbow is tightened with a tourniquet, the skin is treated with an antiseptic and a needle is inserted into the vein, through which blood is taken. As a rule, most people consider this method less painful than giving blood from a finger.
Results of the study
In the laboratory, the total bilirubin is determined in the biochemical blood test - the norm of this enzyme is usually 8.5 - 20.5 μmol / L, although the figures may vary slightly depending on the reagents used in the study. Thus, for each laboratory there is a norm, and its boundaries are necessarily indicated in the results of the analyzes.
So, some sources quote figures, according to which the norm of bilirubin in the blood test is up to 22 μmol / l.
The direct fraction is up to 5.1 μmol / l, and on the indirect - up to 17.1 μmol / l.
Why is bilirubin raised?
On the second-third day after the birth of the body, active destruction of erythrocytes takes place, however, the bilirubin-conjugating system (which turns the indirect fraction of the enzyme into a straight line) is not yet fully formed in newborn children. Because of this, the kids develop physiological jaundice - it goes through 1 - 3 weeks. But what is the norm of bilirubin in the blood of newborns? It is an order of magnitude higher than in adults: on the third - the seventh day after birth, 205 μmol / l of enzyme is fixed (for premature babies - 170 μmol / l). TO
There are several reasons for increasing the level of this bile enzyme in adulthood:
- The number of destroyed erythrocytes is increased, which is the case with hemolytic anemia , for example.
- The liver is damaged and does not cope with the task of removing bilirubin.
- The outflow of bile to the small intestine is disturbed.
- The work of enzymes that form direct bilirubin is disrupted.
If one of the disorders occurs, jaundice begins, in which the color of the mucous membranes, the eye and skin sclera turns yellow.