What is often the first test conducted to diagnose nephrolithiasis?

The first test typically conducted to diagnose nephrolithiasis, or kidney stones, is a non-contrast CT scan of the abdomen and pelvis. This imaging modality is highly sensitive and specific for detecting kidney stones of various sizes and compositions.

CT scans can visualize the stones without requiring contrast, which minimizes potential risks associated with contrast agents, particularly in patients with impaired renal function. Additionally, a non-contrast CT can quickly and effectively assess for complications related to kidney stones, such as hydronephrosis, making it a favored choice in acute settings where rapid diagnosis is crucial.

Other diagnostic options, while useful in certain scenarios, are not as definitive as a non-contrast CT. Ultrasound can be used for patients where radiation exposure is a concern, especially in children or pregnant women, but it has limitations in visualizing stones that are smaller or located in positions that are challenging to assess with ultrasound. An X-ray of the abdomen might reveal certain types of stones (like calcium-based), but many stones are radiolucent and won't be visible. Urinalysis is valuable for checking for hematuria or urinary crystals but does not provide direct imaging of stones. Therefore, the non-contrast CT stands out as the most effective initial diagnostic tool for