Beyond urinalysis: a review of life-course chronic kidney disease screening across health examination systems in Japan.

Chronic kidney disease (CKD) is a major public health problem. Most international guidelines recommend targeted testing of individuals at high risk rather than population-wide screening. In Japan, urinalysis is embedded in health examination systems across the life course. However, the existence of repeated urinalysis opportunities has not necessarily meant that these programs functioned as a coherent CKD screening pathway. Repeated urinalyses were introduced under different legal mandates and for different public health purposes, with substantial variation in target conditions, test components, and follow-up arrangements. In this context, the 2025 policy decision to add serum creatinine to workplace-based health examinations, following sustained advocacy by the Japanese Society of Nephrology and growing recognition of non-proteinuric CKD, marks an important policy turning point. This review provides an overview of Japan's current health examination systems from the perspective of CKD screening throughout the life course. Specifically, this review describes the 3-year-old health examination, school urinary screening, workplace-based health examinations, the Specific Health Checkup, and late-stage elderly medical examinations by focusing on their institutional basis, structure, follow-up pathways, and current limitations. Taken together, Japan's health examination systems provide repeated urinalyses; however, these opportunities do not automatically amount to a coherent CKD screening strategy. This overview highlights the need to clarify target conditions, downstream interventions, outcome measures, and continuity across programs.