Understanding Lab Tests for Narcolepsy
Written by Private MD Labs Medical Writing Team • Last Updated: September 8, 2025
Narcolepsy is a chronic neurological disorder that affects the brain's ability to control sleep-wake cycles, characterized by overwhelming daytime drowsiness and sudden attacks of sleep. While narcolepsy is primarily diagnosed through clinical evaluation and sleep studies, specialized blood tests can provide valuable supporting information by identifying genetic risk factors.
Top Recommended Test
HLA DRB1,DQB1 Low Resolution
This comprehensive test examines both HLA-DRB1 and HLA-DQB1 genes simultaneously, providing a more complete picture of genetic risk factors. The HLA-DRB1*15:01-DQB1*06:02 haplotype combination is particularly strongly associated with narcolepsy development.
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The Role of Blood Testing in Narcolepsy
There is no single blood test that can definitively diagnose narcolepsy. However, genetic testing through blood work can identify specific HLA (Human Leukocyte Antigen) gene variants that are strongly associated with an increased risk of developing narcolepsy. These tests are fundamental for understanding genetic predisposition and can support the diagnostic process when combined with clinical symptoms and sleep studies.
Other Relevant Tests
HLA DRB1 Low Resolution
This test identifies variants of the HLA-DRB1 gene, particularly the HLA-DRB1*15:01 allele, which is strongly associated with narcolepsy. The presence of this genetic marker can help assess an individual's predisposition to developing this neurological sleep disorder.
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HLA DQB1 Low Resolution
This test detects specific variants of the HLA-DQB1 gene that are strongly associated with increased narcolepsy risk. Certain HLA-DQB1 alleles may contribute to the loss of hypocretin-producing neurons in the hypothalamus, which leads to the characteristic symptoms of narcolepsy.
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HLA DRB3,4,5 Low Resolution
This test analyzes additional HLA gene variants, including HLA-DRB5, which is associated with increased risk of developing narcolepsy. Testing these additional genetic markers provides further insight into an individual's genetic predisposition to this chronic neurological disorder.
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Understanding Your Results
It's important to understand that having these genetic markers does not guarantee that someone will develop narcolepsy, nor does their absence rule out the condition. These tests provide risk assessment information that should be interpreted alongside clinical symptoms and other diagnostic evaluations by a healthcare professional.
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.
