Comparison of plasma clearance of iohexol and urinary clearance of inulin for measurement of GFR in children

Am J Kidney Dis. 2011 Jan;57(1):55-61. doi: 10.1053/j.ajkd.2010.07.013. Epub 2010 Sep 25.


Background: Very few studies have been published that compare plasma clearance of iohexol (Cio) with renal clearance of inulin (Cin).

Study design: Diagnostic test study.

Setting & participants: 60 children aged 11.6 ± 4.5 years with different kidney disorders were investigated.

Index test: Plasma Cio calculated from the slope and a single point.

Reference test: Renal Cin with continuous infusion during water diuresis. Results were compared with the correlation coefficients, bias and precision, accuracy percentage, root mean square error, and intraclass correlation.

Other measurements: Measured creatinine clearance and estimated glomerular filtration rate based on serum creatinine level and height.

Results: Mean Cin was 70.7 ± 41.3 (SD) mL/min/1.73 m². Mean differences between Cio and Cin were 2.65 and 2.00 mL/min/1.73 m² for the slope and single-point methods, respectively. Precision was ±16 mL/min/1.73 m² and intraclass correlation was 0.92 in both methods. Proportions of Cio within 30% of Cin were 83.3% and 86.7% for the slope and single-point methods, respectively.

Limitations: A limited number of patients; no adults were studied.

Conclusions: Plasma Cio shows good agreement with renal Cin.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Child
  • Contrast Media / pharmacokinetics*
  • Creatinine / blood
  • Creatinine / urine
  • Glomerular Filtration Rate*
  • Humans
  • Inulin / pharmacokinetics*
  • Inulin / urine
  • Iohexol / pharmacokinetics*
  • Kidney / metabolism*
  • Kidney Diseases / physiopathology


  • Contrast Media
  • Iohexol
  • Inulin
  • Creatinine