At least 1,019 people were given incorrect results from health checks carried out in fiscal 2025, a survey by the Mainichi Shimbun has found, covering a pool of about 13 million screenings. The errors ran to measured values, doctors' findings and assessments, and questionnaire results.
Mistakes in screening results are extremely rare, but the survey shows they do reach examinees. Companies are obliged to have employees undergo health checks, which typically test the body and such measures as blood pressure, blood sugar, lipids and liver function.
Separate checks are offered to self-employed people and older residents, intended to prevent illness and catch it early. The health ministry has no statistics on misreported results, so the scale of the problem had not been known.
Insurance association data used
The Mainichi Shimbun examined screenings arranged through the Japan Health Insurance Association, which covers about 39.7 million employees of small and midsize companies and their dependents as of the end of fiscal 2024. The association commissions medical institutions to carry out the checks, including the specific health screenings aimed at preventing lifestyle-related diseases, and announces each confirmed misnotification.
The survey drew on those announcements to establish how often the errors occur.
The consequences can be serious. Disputes have arisen over illnesses missed because results were misreported, and in June 2026 the Osaka High Court found a medical corporation at fault for a mistake and ordered it to pay compensation.