A Systematic Review and Meta-Analysis of Diagnostic Test Accuracy for Human Toxoplasmosis: Performance, Populations,...

Accurate and timely diagnosis of toxoplasmosis is crucial for clinical management, particularly in high-risk populations. Despite a diverse diagnostic landscape spanning laboratory-based serology, molecular assays, point-of-care (POC) devices, and emerging technologies, a consolidated quantitative synthesis of their performance and clinical readiness is lacking.

This systematic review and diagnostic test accuracy meta-analysis employed a dual-method design, integrating evidence mapping and quantitative synthesis. We searched Embase, PubMed, Scopus, IEEE Xplore, and other databases from January 1, 2010, to December 31, 2025, for studies evaluating diagnostic tests for human toxoplasmosis. Evidence mapping classified technologies by target, specimen, and validation stage (Tiers 0-3). Meta-analysis pooled sensitivity and specificity using bivariate random-effects models for subgroups with sufficient data. Risk of bias was assessed using QUADAS-2.

Evidence mapping identified 175 studies yielding 309 diagnostic test evaluations across 37 target groups, 20 clinical populations, and 11 technological categories. Most studies evaluated conventional laboratory assays (75.9%), followed by point-of-care tests (20.9%) and emerging technologies (3.2%). Meta-analysis included 182 test evaluations (42,287 samples) and showed that accuracy differed by detection target, population, and platform. Among targets, IgG+IgM and IgG avidity demonstrated the strongest combined performance (IgG+IgM sensitivity 94.8% [95% CI 89.4-97.5], specificity 96.7% [93.9-98.3]; IgG avidity sensitivity 90.8% [84.9-94.5], specificity 97.1% [91.7-99.0]), whereas DNA assays showed a rule-in profile with lower sensitivity (66.0% [51.9-77.7]) but high specificity (96.2% [94.3-97.5]). Performance varied across clinical populations, with a notable diagnostic gap in other immunocompromised patients (sensitivity 55.7% [33.1-76.2] despite specificity 97.7% [92.3-99.3]). By platform, POCTs had high specificity (97.4% [95.4-98.5]) and good sensitivity (87.7% [80.3-92.6]) compared with conventional assays (84.7% [80.2-88.3]; 95.5% [94.2-96.6]).

Diagnostic accuracy for toxoplasmosis is highly context-dependent. Serology remains central, with IgG avidity (and high-performing IgG+IgM strategies) supporting infection dating, and POCTs offering rapid, high-specificity rule-in utility when embedded in appropriate clinical algorithms. The persistently reduced sensitivity in immunocompromised populations highlights an urgent unmet need for improved diagnostics and more rigorous, standardized real-world validation.