抗環瓜氨酸肽抗體及類風濕因子在類風濕關節炎的診斷價值

The diagnostic value of anti-cyclic citrullinated peptide antibodies and rheumatoid factor in patients with rheumatoid arthritis

目的：研究抗環瓜氨酸肽抗體及類風濕因子在類風濕關節炎的診斷價值。方法與材料：在145個類風濕關節炎病人及75個非類風濕關節炎病人身上，以酵素免疫分析法測定抗環瓜氨酸肽抗體數值，另外以濁度測定法測量類風濕因子之高低。結果：在145個類風濕關節炎病人中，119 （82.1%）個病人有抗環瓜氨酸肽抗體，116 （80%）個有類風濕因子。抗環瓜氨酸肽抗體的敏感度、專一度、陽性預測率、陰性預測率各別是82.1%、88.0%、93.0%、71.7%；而類風濕因子則各別為80%、62.7%、81.1%、61.0%。若抗環瓜氨酸肽抗體或類風濕因子兩者其一為陽性，則敏感度有88.3%；若兩者皆為陽性，則專一度高達94.7%。在類風濕因子陽性、類風濕因子陰性、及非類風濕關節炎這三組中，抗環瓜氨酸肽抗體的陽性率各為93.1%、37.9%、12.0%。結論：抗環瓜氨酸肽抗體因為有高度的敏感性及專一性，因此是一個診斷類風濕關節炎很好的工具，若抗環瓜氨酸肽抗體及類風濕因子合併使用，可更進一步增加診斷類風濕關節炎的能力。

Objective: To identify the diagnostic value of anti-cyclic citrullinated peptide (anti-CCP) antibodies and rheumatoid factor (RF) in patients with rheumatoid arthritis (RA). Methods: Serum levels of anti-CCP antibodies were determined by enzyme-linked immunosorbent assay, and levels of RF were determined by nephelometry in 145 patients with RA and 75 patients with non-RA rheumatic diseases. Results: Among the 145 patients with RA, 119 patients (82.1%) tested positive for anti-CCP antibodies, and 116 patients (80.0%) tested positive for RF. The sensitivity, specificity, positive predictive value, and negative predictive value of anti-CCP antibodies for diagnosing RA were 82.1%, 88.0%, 93.0%, and 71.7% respectively. Those for RF were 80.0%, 62.7%, 81.1%, and 61.0% respectively. The presence of either anti-CCP antibodies or RF increased sensitivity to 88.3%, and when they both were present, the specificity increased to 94.7%. The positive rates for anti-CCP antibodies in the RF-positive RA, RFnegative RA, and non-RA patients were 93.1%, 37.9%, and 12.0% respectively. Conclusion: With its high sensitivity and specificity, the anti-CCP antibodies assay is a useful test for diagnosing RA. The use of anti-CCP antibodies and RF in combination further increases the diagnostic value for RA.