Ankylosing Spondylitis (HLA-B27) Genotyping
Ordering Recommendation

Not a diagnostic test for ankylosing spondylitis. May assist in the diagnosis of the condition only if other clinical signs and symptoms are present. Test should not be performed for prenatal diagnosis of ankylosing spondylitis because a positive result is not predictive for the disorder.

Polymerase Chain Reaction/Fluorescence Monitoring
3-7 days
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
ARUP Consult®
Disease Topics
Specimen Required
Patient Preparation
Lavender (EDTA), pink (K2EDTA), or yellow (ACD Solution A or B). 
Specimen Preparation
Do not freeze. Transport 3 mL whole blood. (Min: 1 mL) 
Storage/Transport Temperature
Unacceptable Conditions
Plasma or serum; collection of specimen in sodium heparin tubes. 
Ambient: 72 hours; Refrigerated: 1 week; Frozen: Unacceptable 
Reference Interval
Negative: The specimen is negative for HLA-B27.
Positive: The specimen is positive for HLA-B27.
Interpretive Data
Background Information for Ankylosing Spondylitis (HLA-B27) Genotyping:
Ankylosing spondylitis (AS) is a chronic inflammatory disease that primarily causes pain and inflammation of the joints between the vertebrae of the spine and the sacroiliac joints. Inflammation and pain may occur in other parts of the body as well. HLA-B27 is strongly associated with ankylosing spondylitis (AS) as well as with Reiter syndrome, anterior uveitis, psoriatic arthritis, and inflammatory bowel disease.
Greater than 90 percent of patients with AS are HLA-B27 positive compared to 5-10 percent of the general population.
Two to eight percent of individuals with HLA-B27 will develop AS.
Polymerase chain reaction (PCR) and fluorescent hybridization probes.
Analytical Sensitivity & Specificity:
99 percent
Limitations: Rare alleles present in less than 1 percent of most populations will not be detected. Diagnostic errors can occur due to rare sequence variations.

Statement C: Compliance Statement C: For human genetic inheritable conditions and mutations. This test was developed and its performance characteristics determined by ARUP Laboratories. The U. S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.

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

Hotline History
View Hotline History
Component Test Code*Component Chart NameLOINC
0050406Ankylosing Spondylitis (HLAB27)26043-0
2001317Ankylosing Spondylitis (HLAB27) Specimen31208-2
* 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 view this test within the Laboratory Test Directory found at
  • HLA B27 genotyping
  • HLA-B27