The HLA-B27 (PCR) test is a laboratory test used to identify the presence of the HLA-B27 gene variant in a person’s DNA. This gene variant is associated with an increased risk of developing certain autoimmune diseases, particularly ankylosing spondylitis, a type of inflammatory arthritis that affects the spine and other joints. The PCR (polymerase chain reaction) method is a highly sensitive technique that allows for the detection and amplification of small amounts of DNA, making it an accurate and reliable method for detecting the HLA-B27 gene variant. However, it is important to note that the presence of the HLA-B27 gene variant does not necessarily mean a person will develop an autoimmune disease, and the absence of the gene variant does not rule out the possibility of developing an autoimmune disease. The HLA-B27 (PCR) test is usually ordered by a healthcare provider as part of the diagnostic workup for suspected autoimmune disease.