Analytical performance of commercial myositis-specific autoantibody tests evaluated against immunoprecipitation assays as a reference standard: A systematic review and meta-analysis

OBJECTIVE: To evaluate the analytical performance of commercial myositis-specific autoantibody (MSA) assays against immunoprecipitation (IP) assays.

METHODS: A systematic literature search was conducted in PubMed, Web of Science, and Scopus through July 2024. Data were extracted on study design, participant characteristics, index tests, and 2 × 2 contingency tables for diagnostic performance. Study quality was assessed using the QUADAS-2 tool. Sensitivity and specificity were calculated for each dataset and presented as paired forest plots and summary receiver operating characteristic (SROC) curves. A hierarchical SROC model was used to estimate pooled sensitivity and specificity for meta-analysis.

RESULTS: Of 3156 articles, 23 met inclusion criteria and were judged to have low risk of bias across all QUADAS-2 domains. The most frequently evaluated commercial assay was the line blot assay (LBA; 16 studies), followed by enzyme immunoassay (EIA; 9 studies). In the meta-analyses, the highest pooled sensitivity was observed for anti-MDA5 with EIA (95.7 %), followed by anti-SAE with LBA (88.3 %), anti-PL-12 with LBA (87.2 %), and anti-Jo-1 and anti-MDA5 with LBA (82.8 %). Lower sensitivities were observed for anti-Mi-2 (67.4 %), anti-NXP2 (69.7 %), and anti-TIF1-γ (63.8 %) with LBA. Pooled specificity ranged from 94.7 % to 99.3 % across MSA assays, but a false-positive result was a common concern for LBA, except for anti-EJ.

CONCLUSION: False-positive and false-negative results remain a significant challenge in the use of commercial MSA assays.