Renal concentrating capacity as a marker for glomerular filtration rate

Acta Paediatr. 2008 Jan;97(1):96-9. doi: 10.1111/j.1651-2227.2007.00587.x. Epub 2007 Dec 10.


Aim: We have studied 160 children with a variety of renal diseases, 14 of them with chronic renal failure (CRF), to evaluate maximum urinary osmolality as a predictor of glomerular filtration rate (GFR) testing the hypothesis that a normal GFR is necessary to have a normal urinary concentrating capacity.

Methods: All patients had a serum creatinine measured. GFR was calculated according to the Schwartz formula. All patients underwent desmopressin (DDAVP) test to evaluate renal concentrating capacity.

Results: Patients with CRF were unable to concentrate the urine beyond 486 mosm/kg whereas all patients with a normal concentrating capacity (urine osmolality >835 mosm/kg) had a normal GFR. Desmopressin test sensitivity to detect CRF was 100% and specificity 70.5%. A significant negative correlation was found between urinary osmolality after DDAVP administration and serum creatinine levels and between urinary volume corrected by 100 mL of GFR (V/GFR) and urinary osmolality.

Conclusion: In our series, a normal concentrating capacity was always associated with a normal GFR while all patients with decreased GFR had a concentrating capacity defect. Thus, in the evaluation of infants and children with renal disease, the finding of a normal urinary concentrating capacity will suggest and intact glomerular and tubular function.

MeSH terms

  • Adolescent
  • Adult
  • Biomarkers
  • Child
  • Child, Preschool
  • Female
  • Glomerular Filtration Rate / physiology*
  • Humans
  • Infant
  • Infant, Newborn
  • Kidney Concentrating Ability*
  • Kidney Diseases / physiopathology*
  • Male
  • Predictive Value of Tests


  • Biomarkers