Bone histomorphometry for the diagnosis of renal osteodystrophy - a European consensus statement.

Histomorphometric analysis of an iliac bone biopsy remains the gold standard for the diagnosis of renal osteodystrophy (ROD), which comprises various histological lesions induced by chronic kidney disease (CKD). ROD belongs to the framework of CKD-associated osteoporosis. The use of bone biopsy in the routine management of CKD-associated osteoporosis has decreased over the past decades for various reasons, including diminishing expertise in performing the procedure, and major variability in processing bone samples and reporting of results. In this context, the European Renal Osteodystrophy group, a part of the CKD-mineral and bone disorder working group of the European Renal Association launched an initiative to evaluate various issues related to bone histomorphometry in the context of ROD. To this effect, 28 experts from 14 European countries engaged in rounds of discussions to reach a consensus related to the bone biopsy procedure, sample handling, and reading and reporting findings. Key conclusions include a recommendation that all practitioners in this field move towards reporting diagnostic findings by the turnover, mineralization, and volume (TMV) classification and that external quality control is prioritized to ensure validity and reproducibility of results. The consensus group recognises that the lack of an accepted normative reference for bone histomorphometry is a barrier towards uniform diagnostic definitions and recommends further collaborative efforts in this area. Until these issues are solved, transparent reporting on the choice of reference and diagnostic definitions applied should be adhered to, both in clinical reports and research settings.