Age-adjustment of creatinine, i.e. recalculation of childhood levels of creatinine to corresponding levels at 18 years of age and applied in the adult revised Lund-Malmö GFR equation led to markedly improved accuracy in Swedish children (n=1 718) at measured GFR <75 mL/min/1.73 m2 (n=318) and preserved high accuracy at ≥75 mL/min/1.73 m2 (n=1 400). The adjusted LMR equation performed as well as dedicated paediatric equations based on height. The proposed adjustment strategy has four strengths: (i) the original coefficients of the adult GFR equation can be used, (ii) the same equation can be used across the entire lifespan without artificial changes in estimated GFR when switching from paediatric to adult care, (iii) the lack of height factor makes it easier to automatically report estimated GFR by the laboratories and (iv) age-adjusted creatinine values imply that well-established creatinine reference intervals for adults can also be used for children.