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Bilirubin is a bile pigment that comes from the breakdown of red blood cells. Its concentration in the blood allows you to assess the functioning of the liver – an increase in this concentration may cause jaundice. The measurement of the bilirubin index is performed at the request of a doctor for control purposes or when diagnosing diseases.
Direct and indirect bilirubin form total bilirubin – yellow dye, a breakdown product of red blood cells.
Bilirubin is produced during the breakdown of hemoglobin, and more specifically the heme, which is its component. It first enters the plasma, and then goes through the blood to the liver, where it undergoes a series of changes. From there, the bilirubin is excreted into the gallbladder.
The site of bilirubin breakdown is the reticuloendothelial system, which is mainly found in the liver and spleen. It is important that the products of bilirubin metabolism give the stool a brown color (it is modified by intestinal bacteria), and the urine – yellow. Elevated levels of total bilirubin called hyperbilirubinemiamay suggest ailments of various origins.
Total bilirubin in normal blood is not anything but a concern, as opposed to the presence of total bilirubin in the urine – which indicates an illness. A simple general urine test is performed to determine the total bilirubin concentration in the urine. The presence of bilirubin in the urine may raise the suspicion of, for example, liver disease.
If you want to be tested, order a general mail order urinalysis from Medonet Market.
Also read: What is the evidence of elevated bilirubin?
The results of the bilirubin test require interpretation by your doctor. Make an online teleconsultation with your family doctor – this is the fastest way to get your questions answered.
Bilirubin is a marker in laboratory diagnosis that is essential in the diagnosis of diseases including jaundice and gallstones. The bilirubin test is performed when:
- differentiating jaundice;
- liver function assessment;
- suspected hepatitis virus infection;
- suspected damage to hepatocytes (poisoning with fungi, drugs, drugs);
- the presence of symptoms suggesting a disease of the bile ducts and pancreas;
- suspicion of haemolytic anemia.
Bilirubin is also tested in newborns to help diagnose the type of jaundice. They often have physiological jaundice or pathological jaundicewhich can be very dangerous to their health.
Also read: Are yellow eyes a symptom of an illness?
Your doctor may refer you to a bilirubin index test if it suspects that your liver function is abnormal or has a virus infection. The bilirubin test is a single blood sample taken from a vein in the arm, with the patient being fasted for at least eight hours before the test. Before a blood sample is drawn, inform your doctor about any medications you are taking, as these may affect the results of the tests.
The correct concentration of bilirubin depends on the intensity of the breakdown of erythrocytes and the liver function, which includes: proper vascularization of this organ, conditioning the supply of hemoglobin, the ability to esterify bilirubin and a properly functioning bile pole of the liver cell, and the patency of the bile ducts that drain bile from the liver to the intestines. Bilirubin – normal: below 17 µmol / l (1 mg%).
Attention! We can encounter high levels of bilirubin in pregnant women and newborns.
Total bilirubin is: 0,2-1,1 mg% (3,42-20,6 µmol / l)
- newborns 1 day: up to 4 mg / dl (up to 68 µmol / l);
- newborns 3 days: up to 10 mg / dl (up to 17 µmol / l);
- newborns 1 month: up to 1 mg / dl (up to 17,1 µmol / l).
- Direct bilirubin: 0,1–0,3 mg% (1,7–5,1 µmol / l).
- Indirect bilirubin: 0,2–0,7 mg% (3,4–12 µmol / l).
Unconjugated bilurubin is calculated from the difference between conjugated and total bilirubin.
Read more: Bilirubin in a newborn – symptoms, types
In the diagnosis of liver diseases the following are important:
- conjugated bilirubin,
- unconjugated bilirubin,
- ALP – alkaline phosphatase,
- AspAT -aminotransferaza aspargninianowa,
- AIAT – aminotransferase alaninowa,
- GGTP-gammaglutamylotransferase.
All these parameters are taken into account in the diagnosis. In patients suspected of haemolytic anemia, blood counts should be additionally performed.
The decreased bilirubin level is not of great clinical significance.
Elevated bilirubin levels are called hyperbilirubinemia and are divided into two types:
- direct bilirubin (with a predominance of conjugated bilirubin),
- indirect or protein-bound bilirubin (predominance of free bilirubin).
A high level of total bilirubin (with a predominance of free bilirubin) may be a consequence of:
- damage to hepatocytes, i.e. liver cells (e.g. cirrhosis, toxic liver damage, viral hepatitis),
- excessive haemolysis, i.e. destruction of red blood cells (autoimmune diseases, condition after transfusion of group incompatible blood),
- Gilbert’s syndrome or Crigler-Najjar syndrome (congenital damage to bilirubin conjugation by liver cells).
In order to confirm or rule out Gilbert’s syndrome, do the Mail-Order Genetic Test for Gilbert’s Syndrome available on Medonet Market.
In turn, the causes of elevated total bilirubin (with a predominance of conjugated bilirubin) are:
- cholestasis of bile inside the liver (intrahepatic cholestasis) – caused by taking certain medications or autoimmune diseases of the liver,
- extrahepatic cholestasis (blockage of the outflow of bile due to obstruction of the extrahepatic bile ducts, e.g. due to the presence of stones in the bile ducts or a tumor,
- Dubin-Jonson syndrome (a disorder of the excretion of conjugated bilirubin from hepatocytes).
Occasionally, the increase in bilirubin occurs in pregnant women – this condition is called gestational cholestasis, and it is caused by hormonal changes in the pregnant woman’s body. It is a natural condition for a newborn to have high bilirubin levels. To assess the harmfulness of its actions, the following factors are taken into account: the child’s age, the rate of increase in bilirubin concentration and possible prematurity.