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22900 Narcolepsy Associated Antigen (NARC)

Narcolepsy Associated Antigen (NARC)
Test Code: NARCAG
Synonyms/Keywords
Narcolepsy Associated Ag, B
Useful For
Ruling out a diagnosis of narcolepsy​
Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
Whole blood​ ​Yellow top (ACD solution B) ​6 mL ​3 mL
Collection Processing Instructions

​Do not transfer blood to other containers.

Specimen Stability Information
Specimen Type Temperature
Whole Blood ACD-B​ ​Refrigerated (preferred)
​Ambient
Specimen acceptability is based on extracted DNA concentration and not sample age.​ ​
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Mayo Clinic Laboratories Monday through Friday​ 5-9 days​
Polymerase Chain Reaction (PCR)/Sequence-Specific Oligonucleotide Probes (SSO)
Reference Lab
Test 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 Range Information
Interpretive Report
Interpretation
If DQB1*06:02 is not detected, the narcolepsy-associated antigen test result will be reported as negative for DQB1*06:02.
 
If the allele is detected, the result will be reported as positive for DQB1*06:02.
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​81376
Synonyms/Keywords
Narcolepsy Associated Ag, B
Ordering Applications
Ordering Application Description
​Centricity ​Narcolepsy Assoc Ag
​Cerner Narcolepsy Assoc Ag, Blood (82026)​
​COM ​Narcolepsy Assoc Ag. Blood
If the ordering application you are looking for is not listed, contact your local laboratory for assistance.
Specimen Requirements
Specimen Type Preferred Container/Tube Acceptable Container/Tube Specimen Volume Specimen Minimum Volume
(allows for 1 repeat)
Pediatric Minimum Volume
(no repeat)
Whole blood​ ​Yellow top (ACD solution B) ​6 mL ​3 mL
Collection Processing

​Do not transfer blood to other containers.

Specimen Stability Information
Specimen Type Temperature
Whole Blood ACD-B​ ​Refrigerated (preferred)
​Ambient
Specimen acceptability is based on extracted DNA concentration and not sample age.​ ​
Useful For
Ruling out a diagnosis of narcolepsy​
Reference Range Information
Interpretive Report
Interpretation
If DQB1*06:02 is not detected, the narcolepsy-associated antigen test result will be reported as negative for DQB1*06:02.
 
If the allele is detected, the result will be reported as positive for DQB1*06:02.
For more information visit:
Performing Laboratory Information
Performing Location Day(s) Test Performed Analytical Time Methodology/Instrumentation
​Mayo Clinic Laboratories Monday through Friday​ 5-9 days​
Polymerase Chain Reaction (PCR)/Sequence-Specific Oligonucleotide Probes (SSO)
Reference Lab
For billing questions, see Contacts
Outreach CPTs
CPT Modifier
(if needed)
Quantity Description Comments
​81376
For most current information refer to the Marshfield Laboratory online reference manual.