Many people with kidney stones do not have any symptoms. For this reason, kidney stones are sometimes found during a diagnostic imaging exam such as an abdominal X-ray, CT scan, or ultrasound that is being performed for another reason (Antonelli 2015).
Chronic and Recurrent Kidney Stones
After a stone is passed or surgically removed, it is typically analyzed for composition (Antonelli 2015; Curhan 2012). Diagnosis and prevention often relies on the 24-hour urine analysis, a valuable test that evaluates concentrations of calcium, magnesium, potassium, oxalate, citrate, and uric acid, as well as urine pH (LabCorp 2015). Obtaining two separate 24-hour urine analyses is a superior method of evaluation compared to a single test (Xu 2013; Sakhaee, Maalouf 2012; Healy 2012; Curhan 2012; Coe 2015).
Acute Kidney Stones
During acute kidney stone passage, blood tests are usually normal, though an elevated number of white blood cells may be seen (Curhan 2012; UMMC 2013). Red and white blood cells, as well as microscopic crystals, may be detected by urinalysis (Curhan 2012). Conditions that can cause symptoms similar to acute kidney stones include urinary tract infection, kidney infection, diverticulitis, ovarian diseases, appendicitis, and ectopic pregnancy (Aliotta 2015).
A patient’s history, physical exam, and urinalysis often clearly indicate acute kidney stones, and diagnostic imaging may not be necessary to confirm the diagnosis in some cases (UMMC 2013; Curhan 2012). Helical computed tomography (CT) is typically used when diagnostic imaging is necessary (Curhan 2012). Ultrasound is not as sensitive as non-contrast CT but is preferred to limit radiation exposure in children and pregnant women (UMMC 2013; Aliotta 2015; Curhan 2012).