Often stones will pass spontaneously. This depends on the size and location of the stone. 90% of small stones of 5mm or less pass spontaneously. On average the spontaneous passage rate of stones of all sizes is approximately:

  • 25% in the proximal ureter
  • 45% in the mid ureter
  • 70% in the distal ureter

Most urologists advise sieving urine to facilitate chemical analysis of retrieved fragments, especially in the case of recurrent stone formers.

Since the majority of renal stones pass spontaneously, management in the ED should be directed to rapid diagnosis and pain relief with referral to urology indicated for developing complications.