HLA B-27 (PCR) is a genetic test that uses Polymerase Chain Reaction (PCR) technology to detect the presence of the HLA-B27 gene . This gene is associated with autoimmune disorders, particularly ankylosing spondylitis and other spondyloarthropathies . A positive result increases the likelihood of developing these conditions, though it is not definitive on its own. PCR is a highly sensitive method that amplifies specific DNA sequences, providing a precise test for the HLA-B27 allele.