What does bilirubin in the biochemical analysis of blood

Bilirubin is a bile pigment, a product of cell degradation. It must be removed from the body, as it can have a toxic effect on the tissue. If the concentration of bilirubin in the blood rises above the critical norm, it most likely indicates diseases of some organs or systems. It is necessary to undergo examination and treatment in order to prevent further complications of the pathological process. This article will discuss what bilirubin is in biochemical blood analysis and how to understand, looking at the result of your analysis, that it is time for a serious examination of some organs.

Table of Contents:
  • What is bilirubin?
  • Norm of bilirubin in blood
  • Why does bilirubin concentration increase?
  • Symptoms of increased bilirubin
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What is bilirubin?

As already said, it is a bile pigment. But how does it appear and enter the blood? This is the result of the decomposition of red blood cells - red blood cells responsible for the transport of oxygen and nutrients to the tissues and the entrainment of decomposition products from them.

The structure of red blood cells includes hemoglobin - an iron-containing substance, which is responsible for the normal functioning of red cells.

Red blood cells on average "live" 110-115 days. After this time, they break up in special cells located in the bone marrow, spleen, liver, etc. As a result of the breakdown of hemoglobin proteins and bilirubin is released. Its first form, pure, indirect, free, unconjugated bilirubin, is an insoluble crystalline substance that negatively affects tissues and especially brain cells. Due to the fact that such bilirubin is not soluble in water, it can not be directly removed from the body. Read more about indirect bilirubin at http: //vseproanalizy.ru/ biohimicheskiy-analiz-krovi /belki/ nepryamoy-bilirubin-norma-i-otkloneniya.html

However, healthy bilirubin is regularly excreted from tissues. This is possible thanks to the enzyme system located in the liver. Free bilirubin enters along with the bloodstream to the liver, where an enzyme called glucuronyltransferase interacts with the pigment, turning it into soluble or direct( conjugated, bound) bilirubin. The name "direct" is due to the fact that such a pigment is easily captured by direct laboratory methods. Read more about this form in the article "Direct bilirubin in the blood."

In chemical terms, conjugated bilirubin is a combination of pure bilirubin with an acid, a derivative of glucose. This pigment has a yellow-brown color, it is he who gives feces a characteristic shade, because bilirubin leaves the body just by emptying the digestive tract.

Despite the fact that the main part of bilirubin is found in the gallbladder and liver, some proportion is constantly present in the blood. It is this fact that allows for analysis of bilirubin and further diagnosis based on it. Since you already have some information about what is bilirubin in the blood, it is worthwhile to elaborate on what content of this pigment in a blood sample is acceptable.

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Blood bilirubin norm

In medical practice, the quantitative blood content of both direct, indirect, and total bilirubin is taken into account. The norm of bilirubin in children under the age of one month changes almost by day:

  • From birth to the 3rd day: the total bilirubin is normally 23-198 µmol / l;straight line - from 0.5 to 10 µmol / l;indirect - from 22.5 to 188 µmol / l.
  • 3-6 days( µmol / L): 27-209( total);1-11( straight line);26-199( indirect).
  • More than a week( µmol / l): 3.5 - 21( total);0-5( straight);3.5-16( indirect).

Laboratory blood bilirubin standards in the laboratory are determined only for the general and direct indicator. Indirect bilirubin is a calculated parameter, its concentration in the blood is found as total bilirubin minus a straight line.

For blood tests for bilirubin in newborns, blood is drawn from the heel or vein on the head. In an adult, blood is taken from a vein.

The bilirubin norm in the blood of men is the same as that of women and amounts to 7-21 µmol / l for the general indicator, for bound bilirubin: 0-5 µmol / l, for free pigment: 7-16 µmol / l. Read more about bilirubin in women at http: //vseproanalizy.ru/ biohimicheskiy-analiz-krovi /belki/ norma-i-prichinyi-otkloneniya-bilirubina-u-zhenshhin.html

Norm bilirubin in an adult does not depend on gender, specific age or hormonal changes.

The fact that children have much more bilirubin in their blood than in adults is due to the fact that after birth there is an increased disintegration of fetal erythrocytes, the content of which is characteristic only for newborns. It is necessary for more efficient supply of oxygen from the mother to the baby through the placenta. Of course, after some time adapting to a new environment, this type of red blood cells is replaced by the one that is present in adults, and bilirubin normally takes on much smaller values.

The norm of bilirubin in pregnancy corresponds to that for adults. With the growth of the fetus, the value may vary slightly, but this practically does not affect the deviation. But if a pregnant woman had a serious increase in bilirubin, it is necessary to find out the reasons as soon as possible. Some diseases that cause high bilirubin in the blood( hepatitis, hemolytic anemia) may increase the risk of premature birth or loss of a child.

In order to compare the results of your blood test, specify the reference values ​​in the laboratory. Usually, next to your result, it is written what kind of bilirubin should be in the norm or which way your value deviates from the norm.

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Why does bilirubin concentration increase?

Elevated bilirubin in the blood carries important information for the doctor, because it usually helps to identify congenital and acquired diseases.

The concentration of bilirubin in the bloodstream may increase for several reasons:

  • Enhanced hemolysis( disintegration) of erythrocytes.
  • Disruption of enzyme production in the liver, which is responsible for the transformation of the insoluble form into conjugated bilirubin.
  • Disruption of the flow of bile into the bladder.
  • Diseases and destruction of the liver.
  • Extraneous external influence on the body's work( from the side of parasites).

In general, the causes of elevated bilirubin in the blood can be classified into several groups, depending on the affected system of the body.

  1. Circulatory system

This group includes hemolytic anemia, Rh-conflict, blood transfusion, incompatible for humans.

These pathologies are associated with increased destruction of red blood cells, and, consequently, an increased content of their decay products.

Hemolytic disease of the newborn( or jaundice) occurs if the mother’s Rh factor conflicts with the fetus’s Rh factor. In this case, almost immediately after the birth of the child, the unhealthy breakdown of red blood cells begins. During the pregnancy itself, the consequences of such a conflict are not expressed in any way, since the mother’s blood does not enter the bloodstream of the child, but during the birth it mixes up, antibodies are secreted to fight unwanted blood, which together with foreign blood also destroys its own.

  1. General infection of the body

Sepsis, malaria, negative influence of the surrounding atmosphere( lead intoxication, cuprum salts).

These conditions are also accompanied by the accelerated breakdown of red blood cells, which increases bilirubin. In this regard, they are sometimes not separated into a separate group, and referred to as diseases of the circulatory system.

  1. Liver

Parenchymatous, obstructive jaundice, various types of hepatitis, cirrhosis of the liver, infectious lesions of the liver, cancer and penetration of metastases into the organ, etc.

It does not include diseases that are hereditary and change the enzyme system located in the liver.

Bilirubin does not fully bind with cirrhosis of the liver, so the free form circulates through the bloodstream, causing the skin to turn yellow and itchy. In addition, the results of the analysis show a decrease in urea and cholesterol.

Bilirubin in hepatitis C also increases significantly, along with this an increase in the volume of the liver and spleen is found. Hepatitis most often resembles the flu first, accompanied by high fever, general malaise and other associated symptoms. Then the symptoms of jaundice appear.

  1. Enzymes

Since the enzyme system of the liver plays the main role in the conversion of bilirubin from an insoluble compound to a soluble one, its anomalies hinder the normal release of pigment from the body, which is indicated by increased bilirubin.

These diseases include Gilbert, Dabin-Jones syndrome, Rotor, etc.

Typically, such diseases do not require special treatment, although the level of bilirubin must be constantly monitored and maintained at the proper level. Gilbert's disease passes on its own by the age of 45, when the enzymatic system is fully formed.

  1. Gallbladder or bile ducts

Cancer in the bile duct, pancreatitis, Caroli disease, cholangitis, atresia, gallstones, obstructive jaundice and other diseases of this group can be accompanied by an increase in bilirubin, both direct and indirect. At the same time, if the total amount of bilirubin is increased, pathologies of the liver and circulatory system are more likely.

Pay attention to the article "What and how to lower bilirubin in the blood."

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Symptoms of increased bilirubin

Among the obvious signs of a high concentration of bilirubin in the blood can be identified:

  • Yellow eye sclera;
  • Yellow skin;
  • Weakness after slight physical exertion;
  • Pain on the right side under the ribs;
  • Dark urine;
  • Light gray cal.

The last two signs are characteristic only for developed jaundice, they are extremely rare in hereditary diseases.

If you have any additional questions about what shows bilirubin and how to analyze your blood count, leave comments.

God bless you!