Include a urinalysis to detect the presence of blood (hematuria) and bacteria (bacteriuria) in the urine. Other tests include blood tests for creatinine (to evaluate kidney function), BUN and electrolytes (to detect dehydration), calcium (to detect hyperparathyroidism), and a complete blood count (CBC; to detect infection).
Intravenous Pyelogram (IVP)
This test involves taking a series of x-rays after injecting a contrast agent (dye) into a vein. The contrast agent flows through the veins, is excreted by the kidneys, and improves the x-ray images of the kidneys and ureters. If a kidney stone is blocking a ureter, the contrast agent builds up in the affected kidney and is excreted more slowly. Most kidney stones can be precisely located using this procedure. There is a slight risk for an allergic reaction to the contrast agent during this study and overall kidney function must be normal. IVP can take a very long time if the blockage to the kidney is severe and it requires a radiologist be present.
A cystoscopy (i.e., a procedure in which a telescopic instrument is inserted into the bladder) is performed to locate the opening from the urethra to the bladder. The contrast agent is injected directly into this opening and an x-ray is taken to locate the kidney stone.
This procedure eliminates the risk of an allergic reaction to the contrast agent because the dye does not reach the bloodstream, but it may require anesthesia. While a retrograde pyelogram is the most reliable method for visualizing the urinary system and detecting stones, it is generally used only when other imaging methods are inadequate or unsuccessful.