Description

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Objective:

Determine the significance and clinical use of measuring Direct or Conjugated Bilirubin in clinical practice

Lab Test Name:

Direct or Conjugated Bilirubin

Description:

Bilirubin is a substance made when your body breaks down old red blood cells. This is a normal process. Bilirubin is also part of bile, which your liver makes to help digest the food you eat.

A small amount of bilirubin in your blood is normal.

Some bilirubin is bound to albumin in the blood. This type of bilirubin is called unconjugated, or indirect, bilirubin.

In the liver, bilirubin is changed into a form that your body can get rid of. This is called conjugated bilirubin or direct bilirubin. 

This bilirubin travels from the liver into the small intestine. A very small amount passes into your kidneys and is excreted in your urine. This bilirubin also gives urine its distinctive yellow color and contributes to the brown color of stool.

Indications:

• Newborns – immature liver has trouble clearing bilirubin and manifests as jaundice
• Investigate jaundice in adults
• Blockage of bile ducts- (liver or gallbladder)
• Detection of liver disease- particularly hepatitis
• Monitor progression of hepatitis
• Detect issues with RBC breakdown→hemolytic anemia
• Suspected drug toxicity- many medications are metabolized and cleared in the liver

Normal Therapeutic Values:

Normal – 0.0-0.2 mg/dL

Collection:

• Plasma separator tube

What would cause increased levels?

Increased levels linked to:

• Poor liver function or hepatitis
• Certain medications
• Hemolytic anemia
• Pregnancy
• Sepsis- poor perfusion
• Exercise
• TPN
• ETOH

What would cause decreased levels?

Studies are inconclusive regarding risk or association with disease process in the presence of a decreased bilirubin level.