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Test Name:
Narcolepsy-Associated HLA Typing, by PCR
- SBMF No:
44235 - Performance Lab Name:
ARUP Laboratories - Test Mnemonic:
NARC HLA - ABN:
Required – Not FDA-Approved - CPT Code:
83891; 83898; 83912 - LOINC Code:
19146-0 - Ref Lab Test No:
2005023 - Also Known As:
Narcolepsy (HLA-DQB1*06:02) Genotyping - Spec Type:
Whole blood - Spec Container:
Lavender top (EDTA) or pale yellow top (ACD-A or B) tube - Pref Vol:
3.0 mL - Min Vol:
1.0 mL - Fasting:
No - Patient Prep:
Counseling and informed consent are recommended for genetic testing
Consent forms are available online - Spec Collect:
Routine venipuncture - Spec Process:
Gently invert tube to mix blood with the anticoagulant
Do not centrifuge
Do not remove plasma from cells
Forward entire tube of unprocessed whole blood to the laboratory - Spec Store Transport:
Room temperature or refrigerated - Spec Stability:
1 week room temperature (20-30°C)
1 week refrigerated (2-8C)
Frozen (-20°C): Unacceptable - Methodology:
Polymerase Chain Reaction (PCR)
Fluorescence Monitoring - Reference Range:
By report
Interpretive Data:
Background Information for Narcolepsy (HLA-DQB1*06:02) Genotyping:
Characteristics: Narcolepsy is a sleep disorder associated with invalidating excessive daytime sleepiness and cataplexy (the sudden loss of muscle tone triggered by strong emotions). Additionally, disturbed nighttime sleep, sleep paralysis, and hypnagogic hallucinations (occurring in the period between sleep and wakefulness) are common.
Incidence: Narcolepsy affects approximately 1 in 2,000 individuals.
Inheritance: Multifactorial.
Cause: The HLA-DQB1*06:02 allele is strongly associated with narcolepsy, but, by itself, is not causative. Recent studies indicate HLA-DRB1*15 is no longer associated with narcolepsy.
Mutations Tested: HLA-DQB1*06:02 allele.
Clinical Sensitivity: 85-95 percent depending on ethnicity. Greater than 99 percent of affected Caucasians with cataplexy have the HLA-DQB1*06:02 allele.
Clinical Specificity: Less than 1 percent; 15-25 percent of unaffected Caucasians have the HLA-DQB1*06:02 allele.
Methodology: PCR with melting curve analysis.
Analytical Sensitivity and Specificity: 99 percent.
Limitations: This methodology will not differentiate between individuals who are heterozygous (one copy) and those who are homozygous (two copies) for the HLA-DQB1*06:02 allele. Rare diagnostic errors may occur due to primer site mutations. Alleles other than HLA-DQB1*06:02 will not be identified. Other genetic and non genetic factors that influence narcolepsy are not evaluated. - Additional Test Info:
This test is performed pursuant to an agreement with Roche Molecular Systems, Inc.
Genetic Compliance Statement
The performance characteristics of this test were validated by ARUP Laboratories. The U.S. Food and Drug Administration (FDA) has not approved or cleared this test. However, FDA approval or clearance is currently not required for clinical use of this test. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions. ARUP is authorized under Clinical Laboratory Improvement Amendments (CLIA) and by all states to perform high-complexity testing.Counseling and informed consent are recommended for genetic testing. Consent forms are available online.
- Day Run:
Varies - Time Reported:
Within 11 days - Test Type:
GENETIC
