Ordering Recommendation

May help to rule out narcolepsy when clinical history and sleep studies are inconclusive.

New York DOH Approval Status

This test is New York state approved.

Specimen Required

Patient Preparation
Collect

Lavender (EDTA). Also acceptable: Yellow (ACD solution A).

Specimen Preparation

Transport 3 mL whole blood. (Min: 1 mL)

Storage/Transport Temperature

Refrigerated.

Unacceptable Conditions

Specimens collected in yellow (ACD solution B). Clotted, grossly hemolyzed, or heparinized specimens.

Remarks
Stability

Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable.

Methodology

Polymerase Chain Reaction (PCR)/Massively Parallel Sequencing/Sequence-Specific Oligonucleotide Probe Hybridization

Performed

Mon-Fri

Reported

8-15 days

Reference Interval

By report

Interpretive Data

Background Information for Narcolepsy (HLA-DQB1*06:02) Genotyping:
Characteristics:
Narcolepsy is a chronic neurological sleep disorder that manifests in excessive daytime sleepiness and difficulty in maintaining wakefulness. Narcolepsy type 1 is associated with 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: Varies, depending on ethnicity. It affects 0.02-0.05% of the populations in the U.S. and Europe; it is most common in Japan (0.16-0.18%).
Inheritance:  Multifactorial.
Cause:
The HLA-DQB1*06:02 allele is strongly associated with narcolepsy, but by itself is not causative. Homozygosity for DQB1*06:02 allele doubles the risk, compared to heterozygous individuals.  
Alleles Tested:
HLA-DQB1 alleles.
Clinical Sensitivity:
85-95 percent depending on ethnicity. Greater than 98% of affected Caucasians with cataplexy have the HLA-DQB1*06:02 allele.
Clinical Specificity: Less than 1 percent; 15-25 percent of unaffected Caucasians carry the HLA-DQB1*06:02 allele.
Methodology: Polymerase Chain Reaction/Massively Parallel Sequencing, or Polymerase Chain Reaction/Sequence-Specific Oligonucleotide Probe Hybridization
Analytical Sensitivity and Specificity: 99 percent.
Limitations:
Rare diagnostic errors may occur due to primer site mutations. Other genetic and nongenetic factors that influence narcolepsy disease are not evaluated. In cases where an HLA allele cannot be resolved unambiguously, the allele assignment will be reported as the most common, based on allele frequencies from the common, intermediate, and well-documented alleles catalog version 3.0.0 (Hurley CK, et al, 2020).

This test was developed and its performance characteristics determined by the Histocompatibility & Immunogenetics Laboratory at the University of Utah Health. It has not been cleared or approved by the U.S. Food and Drug Administration (FDA). The FDA has determined that such clearance or approval is not necessary. This test is used for clinical purposes. It should not be regarded as investigational or for research. The Histocompatibility & Immunogenetics Laboratory is certified under the Clinical Laboratory Improvement Amendments of 1988 (CLIA-88) as qualified to perform high complexity clinical laboratory testing.

Performed at: Histocompatibility & Immunogenetics Laboratory, University of Utah Health, 417 Wakara Way, Suite 3220, Salt Lake City, UT 84108.

Counseling and informed consent are recommended for genetic testing. Consent forms are available online.

Compliance Category

Performed by non-ARUP Laboratory

Note

Hotline History

N/A

CPT Codes

81382

Components

Component Test Code* Component Chart Name LOINC
3004450 HLA-DQB1, Allele 1 57299-0
3004452 HLA-DQB1, Allele 2 57299-0
3017173 Narcolepsy HLA Interpretation 96625-9
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.

Aliases

  • DQ1
  • DQB1*06:02
  • DR15
  • HLA genotyping for narcolepsy
  • HLA-DQ6
  • HLA-DQB1*06:02
  • Narcolepsy
  • Narcolepsy-Testing
Narcolepsy HLA-DQ Genotyping (HLA-DQB1*06:02)