Narcolepsy Associated Ag, HLA-DQB1 Typing
Test Mnemonic
NARCAB
CPT Codes
- 81383 - QTY (1)
Aliases
- HLA-DQB1*06:02
Performing Laboratory
ARUP
Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 3 mL | Whole blood | EDTA (Lavender) | Refrigerated |
Alternate Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 3 mL | Whole blood | ACD A or B (Yellow) | Refrigerated |
Minimum Specimen Requirements
| Volume | Type | Container | Collect Temperature | Transport Temperature | Special Instructions |
|---|---|---|---|---|---|
| 1 mL |
Stability
| Environmental Condition | Description |
|---|---|
| Refrigerated | 1 week |
| Ambient | 72 hours |
| Frozen | 1 month |
Days Performed
Varies
Turnaround Time
8 - 11 days
Methodology
| Name | Description |
|---|---|
| Fluorescence Monitoring | |
| Polymerase Chain Reaction (PCR) |
Reference Range
| Narcolepsy Ag Interp | |||||
|---|---|---|---|---|---|
| Sex | Age From | Age To | Type | Range | Range Unit |
| Freetext | Refer to Report |
Special Info
Counseling and informed consent are recommended for genetic testing. Plasma, serum and frozen specimens in glass collection tubes will be rejected. This test is New York DOH approved.
Clinical Info
May help rule out narcolepsy when clinical history and sleep studies are inconclusive. Background Information: Characteristics: Narcolepsy is a sleep disorder associated with invalidating excessive daytime sleepiness and cataplexy. 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 not associated with narcolepsy. Mutations Tested: HLA-DQB1*06:02 allele. Clinical Sensitivity: 85-95% depending on ethnicity. Greater than 99% of affected Caucasians with cataplexy have the HLA-DQB1*06:02 allele. Clinical Specificity: < 1%; 15-25% of unaffected Caucasians have the HLA-DQB1*06:02 allele. Methodology: PCR with melting curve analysis. Analytical Sensitivity and Specificity: 99%
Clinical Limitation
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 are not identified. Other genetic and non-genetic factors that influence narcolepsy are not evaluated.