Home
HelpTest ID NARC Narcolepsy-Associated Antigen, HLA-DQB1 Typing, Blood
Useful For
Ruling out a diagnosis of narcolepsy
Method Name
Polymerase Chain Reaction (PCR)/Sequence-Specific Oligonucleotide Probes (SSO)
(PCR is utilized pursuant to a license agreement with Roche Molecular Systems, Inc.)
Reporting Name
Narcolepsy Associated Ag, BSpecimen Type
Whole Blood ACD-BContainer/Tube: Yellow top (ACD solution B)
Specimen Volume: 6 mL
Collection Instructions: Do not transfer blood to other containers.
Additional Information: Specimen acceptability is based on extracted DNA concentration and not sample age.
Specimen Minimum Volume
3 mL
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Whole Blood ACD-B | Refrigerated (preferred) | |
| Ambient | ||
Clinical Information
Narcolepsy is a neurological condition affecting about 0.02% of African American, Caucasian, and Japanese individuals. It is characterized by excessive daytime somnolence and abnormal rapid eye movement (REM) sleep. Cataplexy (weakness precipitated by emotions, especially laughter) is present in 64% to 79% of patients with narcolepsy.
Studies have identified DQB1*06:02 as a useful marker of narcolepsy. DQB1*06:02 is found in 90% to 95% of African American, Caucasian, and Japanese patients with narcolepsy who also have cataplexy (narcolepsy type 1), but only in 45% to 50% of patients with narcolepsy without cataplexy (narcolepsy type 2). It must also be clearly understood that about 25% of normal people have this gene.
Because DQB1*06:02 is present in the normal population, no test for an HLA gene constitutes a test for narcolepsy. A more reliable approach would be to consider that, in an appropriate patient who has cataplexy, the absence of the strongly associated DQB1*06:02, provides good evidence that the patient does not have narcolepsy. However, its absence does not rule-out narcolepsy without cataplexy (narcolepsy type 2).
Reference Values
An interpretive report will be provided.
Cautions
No significant cautionary statements
Day(s) Performed
Monday through Friday; 7:30 a.m.-5:00 p.m.
Report Available
5 daysPerforming Laboratory
Mayo Medical Laboratories in Rochester
Test Classification
This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
81376-HLA Class II typing, low resolution (eg, antigen equivalents); one locus (eg, HLA-DRB1/3/4/5, -DQB1, -DQA1, -DPB1, or -DPA1), each