Preserving kidney stone integrity

Improve accuracy with proper preparation

To optimize laboratory evaluation of kidney stones, specimens must be both clean and dry. The sensitivity of the analytical method used to determine kidney stone composition requires samples be completely dry, since excess water in the stone interferes with the composition analysis and obscures results. Excess blood and tissues in samples can mask the true composition of the stone and potentially result in a false determination that the stone is proteinaceous.

When the receipt of wet or bloody stones requires our laboratories to clean or dry samples prior to analysis, test turnaround times will be extended.

For the highest quality results, follow the kidney stone preparation steps laid out below.

Note: Drying in room-temperature air is recommended. Heat should not be used to dry kidney stones, as it can change the stones’ composition. Mayo Clinic Laboratories dehydrators have separate heat and fan functions. During the drying process, the heat is switched off.

Kidney Stone Prep Part 1: Tools

In the first video of our Kidney Stone Prep series, learn which equipment and tools are required to prepare kidney stones for laboratory evaluation.

Part 2: Regular Stones

The second video in our Kidney Stone Prep series details the steps and techniques required to prepare regular kidney stones for testing, including proper specimen handling, labeling and dehydration.

Part 3: Bloody Stones

Our third Kidney Stone Prep video details the steps required to prepare bloody kidney stones for evaluation. This process entails thorough cleansing of the stones using a vortex mixer to remove blood and residue from the kidney stones before placement in the dehydrator.

Part 4: Stones Embedded in Tissue

In the fourth installment of our Kidney Stone Prep video series, we detail the process for preparing bloody kidney stones embedded in tissue for testing. Appropriate techniques for cleaning, inspection, and dehydration are detailed in this segment.

Part 5: Sock

Part five of our Kidney Stone Prep video series focuses on the necessary steps to prepare for testing kidney stones affixed to a surgical sock. This process entails removing stones from the device, cleaning the sample, and preparing the stones for dehydration.

Part 6: Large, Hard Stone

The sixth video in our Kidney Stone Prep series details the appropriate steps for preparing large, hard stones for testing. The process necessitates a sealable plastic bag and hammer, and entails breaking apart the large stone into smaller pieces before labeling the specimen and placing it in the dehydrator.

Part 7: Dried Stone Transport Container Options

The seventh and final video segment in our Kidney Stone Prep series focuses on transport container options for dried stones, and highlights different tubes for storing and labeling specimens prior to transport.