Meta-Analysis: Diagnostic Accuracy of Antinuclear Antibodies, Smooth Muscle Antibodies and Antibodies to a Soluble Liver Antigen/Liver Pancreas in Autoimmune Hepatitis

Background: Antinuclear antibodies (ANA), smooth muscle antibodies (SMA) and antibodies to a soluble liver antigen/liver pancreas (anti-SLA/LP) are useful markers that can help clinicians to diagnose and classify autoimmune hepatitis (AIH). Objectives: To determine whether ANA, SMA and anti-SLA/LP help to accurately diagnose patients with AIH. Search strategy: The PubMed, CNKI, WANFANG, and SinoMed databases were accessed to retrieve studies published in English and Chinese. Studies published up to October 2013 were reviewed. Selection criteria: Studies on the diagnostic value of ANA, SMA or anti-SLA/LP in the diagnosis of known or suspected AIH were included. Data collection and analysis: Two authors evaluated studies independently and rated their methodological quality using quality assessment of diagnostic accuracy studies (QUADAS) tools; relevant data were abstracted. The random-effects method was used to summarize sensitivities, specificities, positive and negative likelihood ratios, and diagnostic odds ratios (DORs) from all 29 studies. Results: The pooled sensitivity, specificity, positive and negative likelihood ratios, and DOR for ANA were 0.650 (95% confidence interval [CI], 0.619 to 0.680), 0.751 (95% CI, 0.737 to 0.764), 3.030 (95% CI, 2.349 to 3.910), 0.464 (95% CI, 0.356 to 0.604), and 7.380 (95% CI, 4.344 to 12.539), respectively. For SMA, the values were 0.593 (95% CI, 0.564 to 0.621), 0.926 (95% CI, 0.917 to 0.934), 11.740 (95% CI, 7.379 to 18.678), 0.449 (95% CI, 0.367 to 0.549), and 31.553 (95% CI, 17.147 to 58.060), respectively. Finally, for anti-SLA/LP, the values were 0.194 (95% CI, 0.168 to 0.222), 0.989 (95% CI, 0.985 to 0.993), 11.089 (95% CI, 7.601 to 16.177), 0.839 (95% CI, 0.777 to 0.905), and 16.867 (95% CI, 10.956 to 25.967), respectively. Authors' conclusions: ANA provided moderate sensitivity and specificity, while SMA gave moderate sensitivity and high specificity, and anti-SLA/LP exhibited low sensitivity and high specificity. All three antibodies were limited by their unsatisfactory sensitivities and lack of consistency.