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Kidney Stone Analysis

How It Is Done

The kidney stone you take to the lab will be cleaned of any blood or tissue and then looked at to find what chemicals it is made of.

How It Feels

The most common way a kidney stone is collected for this test is by passing it in urine. Passing a stone may be painless or it may be very painful. The pain can begin suddenly and may come and go. A sand-sized stone may pass with little pain. A larger stone may cause a lot of pain in the lower back, groin, or genitals as it moves down the ureters or the urethra.

A small stone may pass without medical treatment. A large stone may need surgery or another type of procedure to get it out.


There is no chance for problems with kidney stone analysis. But a kidney stone can:

  • Have bacteria that can cause a urinary tract infection (UTI).
  • Damage the kidney, especially if the stone is a staghorn (struvite) stone.
  • Block the urinary tract. This can happen while the stone is passing through the tract.


Kidney stone analysis is a test done on a kidney stone to see what chemicals are in it.

Knowing the type of kidney stone helps guide the best treatment choice. Your doctor will talk with you about treatment and prevention measures.

  • About 80% of kidney stones are made of calcium oxalate, calcium phosphate, or a combination of both.1
  • About 10% to 15% of kidney stones are made of magnesium ammonium phosphate (struvite).1
  • About 5% to 10% of kidney stones are made of uric acid.1
  • Less than 1% of kidney stones are made of a chemical called cystine.1

What Affects the Test

Putting tape on a kidney stone to keep it safe on the way to the lab may cause a problem with the test results.

WebMD Medical Reference from Healthwise

Last Updated: November 14, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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