Understanding Lab Tests for Crigler-Najjar syndrome
Written by Private MD Labs Medical Writing Team • Last Updated: September 8, 2025
Crigler-Najjar syndrome is a rare genetic disorder that affects the liver's ability to process bilirubin, a yellow compound produced when red blood cells break down. This condition leads to severe jaundice and requires specific blood testing for diagnosis and ongoing monitoring.
Recommended Test
Bilirubin, Total
This test measures the total amount of bilirubin in the blood and is essential for diagnosing Crigler-Najjar syndrome. In this rare genetic disorder, the liver cannot properly process bilirubin due to enzyme deficiency, causing bilirubin levels to build up significantly. Markedly elevated total bilirubin levels, particularly unconjugated bilirubin, are the primary diagnostic marker for this condition.
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How Crigler-Najjar Syndrome Affects the Body
In Crigler-Najjar syndrome, the liver lacks or has reduced levels of an enzyme called UDP-glucuronosyltransferase, which is essential for converting bilirubin into a water-soluble form that can be eliminated from the body. Without this process, unconjugated bilirubin accumulates in the blood, causing persistent jaundice and potentially serious neurological complications if levels become extremely high.
Diagnosing Crigler-Najjar Syndrome
Blood testing is fundamental for diagnosing Crigler-Najjar syndrome. The hallmark of this condition is severely elevated levels of unconjugated bilirubin in the blood, which can be measured through specific laboratory tests. Early and accurate diagnosis is crucial for proper management and preventing complications.
Monitoring and Management
Regular bilirubin monitoring is essential for individuals with Crigler-Najjar syndrome to track disease progression and treatment effectiveness. Phototherapy and other interventions may be used to help manage bilirubin levels and prevent neurological damage.
Important Considerations
The information here is for educational purposes only and is not a substitute for professional medical advice. Always consult with a healthcare provider for diagnosis and treatment of Crigler-Najjar syndrome.
