From the Research
The absence of hematuria has a relatively low sensitivity for ruling out nephrolithiasis, with a sensitivity of 45% as reported in the most recent study 1. This means that a significant percentage of patients with kidney stones will not have blood in their urine, making the absence of hematuria an unreliable indicator to exclude the diagnosis. Patients with kidney stones can present without hematuria for several reasons:
- the stone may not be causing mucosal irritation or damage,
- the bleeding might be intermittent,
- or the hematuria might be microscopic and missed on dipstick testing. When evaluating a patient with suspected kidney stones, clinicians should rely on a combination of clinical presentation (flank pain, nausea, vomiting), imaging studies (such as non-contrast CT scan, which is the gold standard), and other factors rather than using the absence of hematuria as a definitive exclusion criterion. Even in patients without hematuria who present with symptoms suggestive of nephrolithiasis, further diagnostic evaluation is warranted to avoid missing this important diagnosis, as supported by the findings of 1. It's also worth noting that while other studies such as 2, 3, 4, and 5 provide valuable information on the topic, the most recent and highest quality study 1 should be prioritized when making a definitive recommendation. Therefore, clinicians should not rely solely on the absence of hematuria to rule out nephrolithiasis and should consider further diagnostic evaluation in patients with suspected kidney stones, regardless of the presence or absence of hematuria.