BACKGROUND: Patency confirmation is useful for avoiding the retention of capsule endoscopy (CE). We first evaluated the clinical utility of the tag-less PillCamTM Patency Capsule (PPC) for up to 72 h after ingestion prospectively. METHODS: Excretion of an intact capsule or intact body within 72 h, or positive PPC image in the colon or negative PPC image by abdominal X-ray at 30 h was defined as confirmed functional patency. In patients with unconfirmed functional patency, balloon-assisted enteroscopy was performed to evaluate the reason. RESULTS: Functional patency was confirmed in 44 of 57 patients. Patency was confirmed in 38 patients (66.7%) at 30 h. In 6 of 19 patients (31.6%) in whom patency was not confirmed at 30 h, patency was confirmed within 72 h and no capsule retention (CR) occurred. The rate of pan-enteroscopy did not differ between patients whose patency was confirmed at 30 h and those whose patency was confirmed within 72 h. Excretion time of the PPC significantly correlated with that of the capsule (r = 0.650). Severe adhesions (>5 cm) interfered with PPC passage in 2 patients, despite the absence of critical stricture. The rate of no CR in patients with functional patency confirmed by prior PPC was 97.7%. Misjudgment of the location of the PPC is a risk for CR. CONCLUSIONS: Extending the time to confirm functional patency to 72 h may be acceptable and increase the possibility to perform CE safely in whom CE can perform intrinsically. University Hospital Medical Information Network registration No: 000002564.