The Consistency of Anti-Toxocara IgG Between the Aqueous Humor and Vitreous of Patients With Clinically Suspected Ocular Toxocariasis

Abstract

To assess the consistencies of anti-Toxocara IgG (T-IgG) and Goldmann-Witmer coefficient (GWC) between paired aqueous humor (AH) and vitreous samples from patients with clinically-suspected ocular toxocariasis (OT). Inter-test reliability assessment. A total of 47 patients with clinically-suspected OT who underwent vitrectomy were included. AH, vitreous and serum samples from each patient were collected and levels of specific T-IgG in them were detected. The association and agreement of T-IgG and GWC between AH and vitreous were evaluated. The area under the receiver operating characteristic curve (AUROC) was generated to assess the diagnostic performance of AH. The T-IgG levels and GWC values in vitreous were higher than those in AH (P = 0.023 and P = 0.029, respectively), but similar positivity rates in the T-IgG (P = 1.000) and GWC>3 (P = 1.000) were apparent between vitreous and AH. In addition, there was a positive correlations between the AH and vitreous T-IgG levels (rs = 0.944, P < 0.001) and the GWC values (rs = 0.455, P = 0.022). Moreover, the consistencies between AH and vitreous samples in their T-IgG and GWC positivity rates were almost perfect (both, κ = 0.915, 95% CI, 0.799-1.000) in both. The AUROC reached 0.991, with a 95% confidence interval of 0.971-1.000. The best cut-off value for accurate OT diagnosis was found at 1.434, yielding 96% sensitivity and 100% specificity. Our findings demonstrate that AH and vitreous samples had significant correlations and perfect agreements for both T-IgG and GWC, suggesting that the AH may serve as a proxy for vitreous to provide a safer, earlier, and more convenient screening of OT.