Do you recommend repeat kidney stone composition testing for a patient with recurrent nephrolithiasis who passed an additional stone but previously already had stone composition testing performed?

Good question. Certainly, if there has been a gap in stone events prior to new development of stones, it is reasonable to confirm both the stone composition and the 24-hour urine chemistry, to see if conditions have changed in a meaningful way. It would be less important, if the patient had regular follow up, including 24-hour urine chemistries, and the interval since last stone is expected based on patient's historic pattern. This idea would be particularly relevant if there were several prior ...

Yes. Although the new stone composition may be similar to previously passed stones, that is not always the case. A change in the stone composition may identify new risk factors that would prompt a change in the treatment program.

Stephen B. Erickson, MD