Test Catalog

Test ID: LY27B    
HLA-B27, Blood

Useful For Suggests clinical disorders or settings where the test may be helpful

Assisting in the diagnostic process of ankylosing spondylitis, juvenile rheumatoid arthritis, and Reiter syndrome

Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test

This major histocompatibility coded class I antigen is associated with ankylosing spondylitis, juvenile rheumatoid arthritis, and Reiter syndrome. The mechanism of the association is not understood but probably is that of linkage disequilibrium.


There is an increased prevalence of HLA-B27 in certain rheumatic diseases, particularly ankylosing spondylitis.


Studies have demonstrated that the B*27:06 allele, which is present in a small percentage of individuals of Asian ethnicity, may not be associated with ankylosing spondylitis.

Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.

An interpretive report will be provided.

Interpretation Provides information to assist in interpretation of the test results

Approximately 8% of the normal population carries the HLA-B27 antigen.


HLA-B27 is present in approximately 89% of patients with ankylosing spondylitis, 79% of patients with Reiter syndrome, and 42% of patients with juvenile rheumatoid arthritis. However, lacking other data, it is not diagnostic for these disorders.

Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances

Orders received for both this test and SSO1 / HLA Class I Molecular Phenotype, Blood or DISI / HLA Class I Molecular Typing Disease Association (which provides data on all HLA Class I low-resolution antigens, including B27) will be questioned due to test overlap. This HLA-B27 test is best used alone if a particular disease such as ankylosing spondylitis is under consideration.


Extreme temperature changes during shipping may alter the specimen making it unacceptable for testing.

Clinical Reference Recommendations for in-depth reading of a clinical nature

1. Brewerton DA, Hart FD, Nicholls A, et al: Ankylosing spondylitis and HLA-27. Lancet 1973;1:904-907

2. Albrecht J, Muller HA: HLA-B27 typing by use of flow cytofluorometry. Clin Chem 1987;33:1619-1623