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Test Code NARC Narcolepsy-Associated Antigen, HLA-DQB1 Typing, Blood

Reporting Name

Narcolepsy Associated Ag, B

Useful For

Ruling out a diagnosis of narcolepsy

Performing Laboratory

Mayo Medical Laboratories in Rochester

Specimen Type

Whole Blood ACD-B

Specimen Required

Container/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)

Reference Values

An interpretive report will be provided.

Day(s) and Time(s) Performed

Monday through Friday; 7:30 a.m.-5:00 p.m.

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

LOINC Code Information

Test ID Test Order Name Order LOINC Value
NARC Narcolepsy Associated Ag, B In Process


Result ID Test Result Name Result LOINC Value
NARC_ Narcolepsy Associated Ag Result 53938-7
NARCC Interpretation No LOINC Needed

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).

Analytic Time

5 days

NY State Approved


Method Name

Polymerase Chain Reaction (PCR)/Sequence-Specific Oligonucleotide Probes (SSO)