From Kato-Katz to PCR: Evaluating the evolution of diagnostic techniques for soil-transmitted helminths

Background: Soil-transmitted helminth (STH) infections remain a major public health challenge in low-resource settings, necessitating accurate diagnostic tools to inform mass drug administration (MDA), surveillance, and elimination programs. The Kato-Katz technique is widely used because it is inexpensive, simple, and field-friendly; however, its sensitivity declines markedly in low-intensity infections, low-prevalence communities, and post-MDA settings. In contrast, PCR-based diagnostic approaches offer substantially higher sensitivity and enable reliable detection of low-level, mixed, and species-specific infections. This narrative review summarizes recent developments in STH diagnostics by comparing the diagnostic performance of Kato-Katz and PCR-based methods. Literature from PubMed, Scopus, and Google Scholar published between 2020 and 2025 was analyzed to assess diagnostic accuracy, strengths, and limitations. Across the included studies, conventional PCR, quantitative PCR (qPCR), and multiplex PCR consistently detected approximately 2–10 times more STH infections than Kato-Katz, particularly for Ascaris lumbricoides, Trichuris trichiura, and hookworm in low-intensity and post-MDA settings. While Kato-Katz remains practical for large-scale baseline surveys in high-burden areas, the integration of molecular diagnostics substantially improves surveillance precision and better supports elimination-oriented strategies.