Staples A, et al. - Researchers compared venous and finger stick methods of measuring glomerular filtration rate by iohexol disappearance (iGFR) in children and adolescents 1 to 21 years with stages I–IV chronic kidney disease (CKD) enrolled in this cross-sectional study. After iohexol was infused, blood was drawn 10, 30, 120, and 300 min later. Following each of the latter two blood draws, blood spots on filter paper were collected by finger stick. They calculated GFR by using rate of iohexol plasma disappearance. The two methods were compared using Pearson’s correlation coefficient and bias, Students t test, and Bland-Altman graphical representations. This study included 41 patients. The mean creatinine was estimated to be 1.13 mg/dL, the mean 4-point iGFR was 73.2 ml/min/1.73m² and the mean 2-point iGFR was 75.6 ml/min/1.73m². Findings revealed a high correlation and good agreement between the 2-point iGFR and the 4-point iGFR. Same was found for the dried blood spot (DBS) method and the 2-point venous method. An acceptably accurate measurement of GFR was attained via DBS sampling by finger stick sampling at 2 time points after iohexol infusion.