May assist in the diagnosis of ankylosing spondylitis and a few other rheumatic disorders. HLA-B27 testing is routinely used to screen for AS since 90% of patients with AS have the HLA-B27 surface antigen compared to only 8% of healthy individuals.
HLA-B27 is a serologically defined allele of the human HLA-B locus. The presence of the HLA-B27 antigen is strongly associated with ankylosing spondylitis and related disorders. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions. Anti-HLA-B27 may cross-react with several of the HLA-B antigens, most commonly with the HLA-B7 antigen, leading to a low level of false-positive results. Clinical correlation is required for complete interpretation.