Combined detection of HLA-B27, ESR, and CRP as biochemical and immunogenetic markers in the auxiliary diagnosis of ankylosing spondylitis

Background: Ankylosing spondylitis (AS) is a chronic inflammatory disease in which early diagnosis is often challenging due to atypical clinical manifestations. Laboratory biomarkers such as human leukocyte antigen-B27 (HLA-B27), erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) play an essential role in diagnostic evaluation. Methods: A total of 120 AS patients and 100 healthy controls were enrolled. Venous blood samples were analyzed for HLA-B27 (flow cytometry), ESR (Westergren method), and CRP (immunoturbidimetry). The Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) was assessed, and diagnostic performance was evaluated using receiver operating characteristic (ROC) curve analysis. Results: HLA-B27 positivity was significantly higher in the AS group than in controls (92.5% vs. 5.0%, P< 0.001). Both ESR and CRP levels were markedly elevated in AS patients and showed a progressive increase with higher BASDAI scores (P< 0.05). ROC analysis demonstrated superior diagnostic efficacy of combined HLA-B27, ESR, and CRP detection (AUC=1.000, sensitivity 97.2%, specificity 93.3%) compared with single markers. Conclusions: The combined detection of HLA-B27, ESR, and CRP provides a reliable laboratory-based diagnostic approach for ankylosing spondylitis, enhancing accuracy and clinical applicability. These findings highlight the importance of integrating biochemical and immunogenetic markers into routine diagnostic practice.