The bilirubin test is used to evaluate the functioning of the liver and the gallbladder, as well as possible hepatic lesions. Bilirubin is a substance resulting from the metabolism of hemoglobin (substance in the blood carrying oxygen gives the red color to red blood cells).
When red blood cells, also known as erythrocytes, age, they are picked up and destroyed by the spleen. Hemoglobin is then "broken" and transformed into bilirubin, which in turn is metabolized and excreted by the liver. Bilirubin is also excreted by bile and eliminated through feces.
THE indirect bilirubin is the first bilirubin to be produced in this process, and then transformed into bilirubin.
Thus, when indirect bilirubin is high, it is a sign of increased hemoglobin degradation or impaired liver function. Already the increase of direct bilirubin has as its main cause the deficiency of bile in eliminating bilirubin.
The simultaneous elevation of direct and indirect bilirubin levels may be caused by bile obstruction or severe liver cell injury.
Between the diseases that can increase blood bilirubin concentration are hepatitis, liver cirrhosis, Gilbert syndrome (benign and genetic condition that causes elevated bilirubin levels), liver cancer, sickle cell anemia, gallstones or gallstones, among others.
We adults, normal bilirubin reference values are:
- Total bilirubin: 0.20 to 1.00 mg / dL;
- Direct bilirubin: 0.00 to 0.20 mg / dL;
- Indirect bilirubin: 0.20 to 0.80 mg / dL.
In premature newborns, the normal reference values for total bilirubin are:
- 1 day: 1.00 to 8.00 mg / dL;
- 2 days: 6.00 to 12.00 mg / dL;
- 3-5 days: 10.00 to 14.00 mg / dL.
To the term newborns, the normal reference values for total bilirubin are:
- 1 day: 2.00 to 6.00 mg / dL;
- 2 days: 6.00 to 10.00 mg / dL;
- 3-5 days: 4.00 to 8.00 mg / dL.
The assessment of the blood test result of bilirubin is the responsibility of the hepatologist.
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