Bilirubin

Japanese: ビリルビン

Reference value

Total bilirubin: 0.2-1.2 mg/dL

Direct bilirubin: 0.1-0.5 mg/dL

What is bilirubin?

A pigment produced when hemoglobin in red blood cells breaks down. It is processed by the liver ( Conjugation Notification The bilirubin that is produced is called indirect bilirubin, and the bilirubin that is produced after it has been processed is called direct bilirubin.

Jaundice: Yellowing of the whites of the eyes and skin

Direct bilirubin: Increases when the liver or bile duct is damaged.

Indirect bilirubin Increases when hemoglobin in red blood cells is broken down

This is a test to check for abnormalities in the liver, bile duct, blood, etc. High bilirubin levels often indicate liver dysfunction, so various liver function tests are performed to understand the condition.

High levels due to jaundice: Total bilirubin

Total bilirubin, which is both indirect and direct, is mainly jaundice Royal The yellowing of the skin and eyes is caused by an increase in bilirubin, and when the total bilirubin concentration in the blood reaches 2.0 mg/dℓ or higher, the white part of the eye starts to turn yellow, and if it increases further, the skin will also turn yellow.

High levels due to hemolytic disease…indirect bilirubin

Hemolysis is the abnormal destruction of red blood cells due to some cause. If you have a hemolytic disease, indirect bilirubin that has not yet been processed (conjugated) by the liver increases in the blood.

Direct bilirubin increases due to liver dysfunction, bile duct stones, and tumors

When the liver is damaged, the amount of direct bilirubin processed by the liver increases in the blood. Also, when the bile duct is blocked by gallstones or tumors, the amount of direct bilirubin excreted in the bile increases.

Indirect bilirubin is total bilirubin minus direct bilirubin

Bilirubin is quantified by measuring the color change that occurs when it binds to a special pigment.

In the test, total bilirubin and direct bilirubin are measured, and indirect bilirubin is calculated by subtracting direct bilirubin from total bilirubin. The standard values are 0.2-1.2 mg/dL for total bilirubin and 0.1-0.5 mg/dL for direct bilirubin. The upper limit for total bilirubin is the pathological identification value (constitutional jaundice).

Bilirubin increases when you are fasting and decreases after meals. It also increases with exercise, so please refrain from strenuous exercise the day before and the day of the test.

Identify which bilirubin is increased and find the cause

Bilirubin, not only total bilirubin but also whether indirect or direct bilirubin is increased, is an important indicator in pathological analysis.

If the value is borderline, prolonged fasting or regular medication may be the cause, so the test should be repeated one week after eating or after stopping the medication.

Since high bilirubin levels are often caused by liver dysfunction, various liver function tests are performed to determine the condition.

Direct and indirect bilirubin

Direct bilirubin is bilirubin that has been conjugated in the liver, and is so named because it reacts directly with the test reagent, while indirect bilirubin is so named because it only reacts with the test reagent after caffeine or alcohol has been added.

The main diseases suspected are

◆ High levels → hemolytic jaundice, hepatocellular jaundice (acute hepatitis, cirrhosis), intrahepatic cholestasis (drug-induced hepatitis, primary cholestatic cirrhosis), neonatal jaundice, constitutional jaundice, extrahepatic cholestasis (common bile duct stones, common bile duct tumors), etc.

◆ Low value → Iron deficiency anemia, etc.

The general term used by doctors is "bilirubin"

Source: Hoken "4th Edition: A book that explains the tests you will receive at the hospital" Information about the 4th Edition: A book that explains the tests you will receive at the hospital

Japanese:

基準値

総ビリルビン：0.2～1.2mg/dℓ

直接ビリルビン：0.1～0.5mg/dℓ

ビリルビンとは

　赤血球中のヘモグロビンが壊れてできる色素。肝臓で処理（抱合ほうごう）されて、胆汁を介して十二指腸に排泄される。ビリルビンには3つあり、肝臓で処理される前のビリルビンを間接ビリルビン、処理されたあとのビリルビンを直接ビリルビン、両方をあわせたものを総ビリルビンと呼ぶ。

●黄疸　白目や皮膚が黄色くなる

●直接ビリルビン　肝臓や胆管が障害を受けると増加

●間接ビリルビン　赤血球中のヘモグロビンが壊れると増加

肝臓、胆管、血液などの異常を調べる検査です。ビリルビンの高値は、肝機能障害を示していることが多いため、種々の肝機能検査を行い病態を把握します。

黄疸で高値に…総ビリルビン

　間接と直接の両方をあわせた総ビリルビンは、おもに黄疸おうだんを確認する検査です。肌や眼が黄色くなるのは、ビリルビンが増加するためで、血液中の総ビリルビン濃度が2.0mg/dℓ以上になると、眼球の白い部分が黄色になり始め、さらに増えると皮膚も黄色になってきます。