title: Diagnostic Value of Serum IgG4 for IgG4-Related Disease: A PRISMA-compliant Systematic Review and Meta-analysis.
abstract: Many studies about serum IgG4 for the diagnosis of IgG4-related disease (IgG4-RD) have been reported. However, these studies had relatively small sample sizes and the diagnostic accuracy values varied much between them.The aim of this study was to perform a meta-analysis to evaluate the diagnostic value of serum IgG4 for IgG4-RD.We conducted a search of relevant articles using MEDLINE, EMBASE, Web of Science, SCOPUS, and Cochrane Library databases published before December 2015.Studies those assessed the diagnostic accuracy of serum IgG4 for IgG4-RD and those provided the cut-off value for serum IgG4 were included.Data were synthesized using the random-effect model. Statistical analysis was performed using STATA with the MIDAS module and Meta-DiSc 1.4 software.A total of 9 case-control studies were analyzed, which included 1235 patients with IgG4-RD and 5696 overall controls. The pooled estimate, for a cut-off value ranged from 135 to 144 mg/dL, produced a sensitivity of 87.2% (95% CI, 85.2-89.0%) and a specificity of 82.6% (95% CI, 81.6-83.6%). The positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR) were 6.48 (95% CI, 3.98-10.57), 0.14 (95% CI, 0.09-0.21), and 45.15 (95% CI, 23.41-87.06), respectively. The area under the curve (AUC) of the summary receiver operating characteristic curve (SROC) was 0.94 (0.92-0.96). When a cut-off value of 2-fold the upper limit of normal was used (ranged from 270 to 280 mg/dL), the pooled sensitivity was 63% (95% CI, 60.0-66.0%), and the specificity was 94.8% (95% CI, 94.1-95.4%). The PLR, NLR, and DOR were 13.3 (95% CI, 7.39-24.0), 0.41 (95% CI, 0.29-0.58) and 33.42 (95% CI, 13.88-80.43), respectively. The AUC of the SROC was 0.92 (0.90-0.94).Only a relatively small number of studies were included, and significant heterogeneity was observed in this meta-analysis.Serum IgG4 is a modestly effective marker to diagnose IgG4-RD. Doubling the cut-off value for IgG4 could not improve the overall test characteristics. A high specificity inevitably accompanies with a significant sacrifice in sensitivity.
authors.affiliation: From the National Center for Clinical Laboratories (MH, GF, XY, JL), Beijing Hospital; Graduate School (MH, GF, XY, JL), Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing; Department of Clinical Laboratory (MH), Qianfo Mountain Hospital of Shandong University; and Department of Clinical Laboratory (ML), Jinan Dermatosis Prevention and Control Hospital, Jinan, People's Republic of China.
authors.forename: Mingju
authors.initials: M
authors.lastname: Hao
authors.forename: Min
authors.initials: M
authors.lastname: Liu
authors.forename: Gaowei
authors.initials: G
authors.lastname: Fan
authors.forename: Xin
authors.initials: X
authors.lastname: Yang
authors.forename: Jinming
authors.initials: J
authors.lastname: Li
mesh_terms: D001327:Autoimmune Diseases / Q000097:blood*; D015415:Biomarkers; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D016017:Odds Ratio; D012372:ROC Curve; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D007074:Immunoglobulin G