Asymptomatic Stone Passage Rates
The available evidence does not directly address what percentage of patients pass ureteral stones completely without noticing symptoms, as virtually all published studies focus on symptomatic patients who present for medical care. However, the data on spontaneous passage rates in patients with minimal intervention can provide some insight into this question.
What the Evidence Actually Shows
The guideline literature and research studies exclusively examine patients who are already symptomatic enough to seek medical attention and receive imaging confirmation of stones 1, 2. These studies report:
- 68% of stones ≤5 mm pass spontaneously in patients under observation (95% CI: 46% to 85%) 1
- 47% of stones 5-10 mm pass spontaneously (95% CI: 36% to 59%) 1
- 64% overall spontaneous passage rate across all stone sizes and locations in a large systematic review of 6,642 patients 2
The Critical Gap in Knowledge
None of these studies capture truly asymptomatic patients who never seek medical care. The populations studied include:
- Patients with renal colic severe enough to present to emergency departments 2, 3
- Patients requiring pain medication and clinical follow-up 4
- Patients undergoing CT imaging for suspected stones 5
Clinical Reality and Inference
It is clinically implausible that a significant percentage of patients pass ureteral stones without any awareness, because:
- The average time to stone passage is 17 days (range 6-29 days) for symptomatic stones 2
- Even small stones (≤2 mm) take an average of 8.2 days to pass 4
- Ureteral stones cause obstruction and distension that typically produces at least some discomfort 1
- Studies consistently show that 75% of stones <5 mm pass spontaneously, but these patients still experienced symptoms prompting medical evaluation 2
Bottom Line
The percentage of patients who pass ureteral stones completely asymptomatically (without noticing) cannot be determined from existing medical literature, as all published data comes from symptomatic patients who sought medical care. While some patients may experience minimal symptoms, the natural history studies suggest that most ureteral stones produce at least some recognizable discomfort during passage 1, 2, 4.