After the stone is removed, it is sent for analysis. We will have an idea of what type of stone this is. This may not be enough, especially in patients with recurring episodes of kidney stones. One has to study the urine (24-hour urine collection), and the blood to see what was the cause of this specific type of stone formation. This is especially important, as there are multiple kinds of kidney stones. The most common is made up of calcium oxalate.
The metabolic study of kidney stones consists of blood tests and 24-hour urine collection.
24-hour urine collection:
On the first visit to the lab, the patient is given a jug to collect their urine at home for 24 hours, on a regular diet. This is done from 7am to 7am the next day. Then the urine is brought in to the lab and blood is obtained from the patient to compare the values.
After two weeks, the patient is seen in the office where results are discussed and he or she is placed on a special diet and/or given special medication. While on this diet or medication, the patient will be instructed to collect another 24-hour urine sample to make sure the treatment is working. If the treatment is not working, the dose/diet is adjusted. Repeating the work-up in a year may be advisable. It is my impression that most patients who have done this metabolic work-up have done very well and have not had any recurrent kidney stones.
If the patient does not choose to have the work-up, then a diet consisting of low salt, low oxalate, and low protein is advised. Increased fluids up to 120 ounces daily is advised, and has been known to prevent kidney stones.
