Skip to main content

“Trust my morphology”, the key message from a kidney stone

Dear Editor,

The Consensus Conference Group recently published an article in Urolithiasis highlighting the importance of urine and stone analysis in the metabolic evaluation of kidney stone formers (KSF) [1]. Indeed, each kidney stone contains the imprints of the conditions which created them during their ‘lifetime in the kidney’.

The morpho-constitutional classification method (MCC) established by Prof Michel Daudon correlates the morphological characteristics of stones with specific metabolic disorders [2]. Briefly, it distinguishes 7 types and 21 subtypes according to the crystalline composition and shape, color and structure of stones identified using an optical stereo-microscope (Table 1). This very specific method is easy to learn and provides the opportunity to quickly identify highly recurrent diseases, sometimes serious in their clinical consequences. Indeed, subtypes Ic, Ie, IIId, IVa2 and V are pathognomonic of specific clinical entities corresponding to primary hyperoxaluria type 1, enteric hyperoxaluria, hyperuricosuria with diarrhea, distal tubular acidosis and cystinuria, respectively. In 2019, the International COllaborative NEtwork on Kidney sTones (ICONEKT) encouraged medical community to integrate this method for rapid identification of disorders responsible for the highly recurrent diseases [3]. Despite growing evidence of the robust diagnostic value of Daudon’s MCC and its benefits in drawing up individualized treatment plans, this simple tool unfortunately still remains underexplored. Given the increasing prevalence of KSF and the worrying rise in cases in groups previously considered to be at lower risk of stones (for example, women and children), the aim of our “call to action letter” is to support the position of accurate stone analysis elegantly highlighted by the Consensus Conference that you recently published [1]. In this way, we hope to raise interest and encourage more physicians to consider Daudon’s MCC as a priority in their clinical practice in order to improve the care of KSFs.

Table 1 Daudon’s morpho-constitutional classification of kidney stones, main characteristics and corresponding etiologies


  1. 1.

    Williams JC Jr, Gambaro G, Rodgers A, Asplin J, Bonny O, Costa-Bauza A et al (2021) Urine and stone analysis for the investigation of the renal stone former: a consensus conference. Urolithiasis 49:1–16.

    Article  PubMed  Google Scholar 

  2. 2.

    Daudon M, Bader CA, Jungers P (1993) Urinary calculi: review of classification methods and correlations with etiology. Scanning Microsc 7:1081–1104

    CAS  PubMed  Google Scholar 

  3. 3.

    Pozdzik A, Maalouf N, Letavernier E, Brocheriou I, Body JJ, Vervaet B et al (2019) Meeting report of the “Symposium on kidney stones and mineral metabolism: calcium kidney stones in 2017.” J Nephrol 32:681–698.

    Article  PubMed  Google Scholar 

Download references

Author information



Corresponding author

Correspondence to Agnieszka Pozdzik.

Ethics declarations

Conflict of interest

The authors declare that they do not have conflict of interest.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Pozdzik, A., Van Haute, C., Maalouf, N. et al. “Trust my morphology”, the key message from a kidney stone. Urolithiasis 49, 493–494 (2021).

Download citation