Your STONE score estimates the probability that your flank pain is caused by a ureteral stone. A low score (0 to 5) corresponds to approximately a 10% probability of ureterolithiasis, meaning most patients in this range have an alternative diagnosis such as musculoskeletal pain, pyelonephritis, or ovarian pathology. A moderate score (6 to 9) indicates roughly a 50% probability, placing the diagnosis in an uncertain zone that typically warrants imaging confirmation. A high score (10 to 13) indicates approximately a 90% probability of a ureteral stone, providing strong clinical confidence in the diagnosis.

The score is most useful for guiding imaging decisions. In the high-probability group, the diagnosis is sufficiently likely that some clinicians may forgo CT scanning in select cases (particularly young patients where radiation exposure is a concern) and proceed with empiric management and ultrasound. In the low-probability group, the differential diagnosis is wide and further workup targeting alternative causes may be more productive than a CT specifically for stones.

The STONE score is designed for use in the emergency department when evaluating patients who present with acute flank pain suspicious for renal colic. It is most valuable when deciding whether to obtain a non-contrast CT abdomen and pelvis, the gold standard for stone diagnosis but a source of ionizing radiation and healthcare costs.

It is particularly helpful in situations where imaging resources are constrained, such as in urgent care centers or resource-limited settings. For patients with a high STONE score and classic clinical presentation, clinicians may choose an ultrasound-first approach or empiric trial of analgesics and hydration. For patients with low scores, the tool redirects clinical attention toward alternative diagnoses that may require different imaging or workup.

The STONE score was derived and validated in US emergency department populations and may not generalize equally to all settings or demographics. The inclusion of race as a scoring variable (non-Black patients receive additional points) reflects epidemiologic data on nephrolithiasis prevalence but may be viewed as a limitation of the score's construction.

The score predicts the probability of having a stone but does not assess stone size, location, likelihood of spontaneous passage, or the presence of complications such as hydronephrosis, infection, or renal impairment. These clinically important factors still require imaging and laboratory evaluation. A high STONE score does not eliminate the need for CT in patients with signs of complicated stone disease (fever, solitary kidney, persistent vomiting, or elevated creatinine).

The STONE score also does not account for prior stone history, which is one of the strongest clinical predictors of recurrent nephrolithiasis. Clinicians should integrate the score with the full clinical picture rather than using it in isolation.