Comparison of Maxwell Kit-Based and NaOH-Based DNA Extraction Incorporated copro-DNA-SjTR1-qPCR Systems: Insights from Detecting Low-Intensity Schistosoma Japonicum Infections

Schistosomiasis remains a significant public health issue globally. This study aimed to compare the performance of two molecular diagnostic systems for the detection of low-intensity Schistosoma japonicum infections. A Maxwell kit-based copro-DNA- SjTR1 -qPCR workflow ( SjTR1 -qPCR-S1) and a NaOH-based copro-DNA- SjTR1 -qPCR workflow ( SjTR1 -qPCR-S2) were compared as integrated systems using faecal samples ( n = 554) collected from an S. japonicum -endemic area in Leyte Province, the Philippines. The duplicated Kato–Katz (KK) was performed on three stool samples collected from different days for each participant. The diagnostic performance of KK and the SjTR1 -qPCR systems were comprehensively compared with a composite reference where a participant was classified as positive if the KK was positive or any qPCR assay was positive. The KK, SjTR1 -qPCR-S1 and SjTR1 -qPCR-S2 recorded positivity rates of 25.1% (139/554), 25.5% (141/554) and 29.8% (165/554), respectively. The overall S. japonicum positivity rate was 39.2% (217/554) as determined from the composite reference. Both SjTR1 -qPCR systems exhibited excellent sensitivity in individuals with moderate-heavy (eggs per gram ≥ 100) and light (eggs per gram 10–99) infection intensity, with reduced sensitivity observed only in individuals with extremely low egg burden (eggs per gram 1–9). Globally, SjTR1 -qPCR-S2 demonstrated significantly higher sensitivity (76.0%) compared with the KK (64.1%) and SjTR1 -qPCR-S1 (65.0%) [ p < 0.0161 and p = 0.0021, respectively, χ 2 m ]. For samples positive in both SjTR1 -qPCR systems ( n = 125), SjTR1 -qPCR-S1 showed a significantly higher median Ct value than SjTR1 -qPCR-S2 ( p < 0.0001, Wilcoxon signed-rank test). Both SjTR1 -qPCR systems showed a significant negative correlation between Ct values and faecal egg counts ( ρ = – 0.5947 for SjTR1 -qPCR-S1, and ρ = – 0.4844 for SjTR1 -qPCR-S2, both p < 0.0001). Moderate agreement was observed between both SjTR1 -qPCR systems and the KK ( κ = 0.560 and κ = 0.512, respectively). However, substantial agreement was found between SjTR1 -qPCR-S1 and SjTR1 -qPCR-S2 ( κ = 0.748). The combined qPCR systems showed a sensitivity of 83.4%. SjTR1 -qPCR-S2 is cost effective and less reliant on specialised equipment compared with SjTR1 -qPCR-S1. With further optimisation, the SjTR1 -qPCR-S2 system can be a powerful and game-changing option for integration into the current surveillance network to support the eradication of schistosomiasis japonica.