Glomerular filtration rate measured by XXXX clearance: A comparison of venous samples and capillary blood spots.

@entity1 @entity1009 @entity740 @entity6111
BACKGROUND: Glomerular filtration rate (GFR) measured by @entity6111 clearance using venous samples is widely used. Capillary sampling on filter paper is easier to perform, may be less painful and spares the blood volume. The purpose of the study was to validate a blood spot method for measuring GFR in @entity1 aged 6 years or younger suffering from @entity740 ( @entity740 ). METHODS: We examined 32 @entity1 with @entity740 , median age (range) 3.0 (0.3-6.2) years. Seven venous samples (10, 30/60, 120, 180, 210, 240, 300 min) were collected and GFR based on all samples was calculated for reference. Following injection of @entity6111 , blood spots were collected at 120, 180, 210 and 240 min and compared to the reference @entity6111 clearance. RESULTS: Median (range) reference GFR was 65 (6-122) mL/ @entity1009 .73 m(2). The 2, 3 and 4-point blood spot GFR were highly correlated to the reference GFR (r = 0.947, 0.945, 0.937). The mean relative bias between 2-point blood spot and reference GFR was 7.2%, and only 2.3% in the @entity1 with reference GFR < 60 mL/ @entity1009 .73 m(2). The diagnostic accuracy for 2-point blood spot was: 87.5% and 96.9% within    15% (P15) and    30% (P30) of the reference GFR respectively. In @entity1 with GFR < 60 mL/ @entity1009 .73 m(2), both P15 and P30 were 100%. CONCLUSIONS: GFR calculation based on blood spot @entity6111 measurement is an alternative method to traditional venous @entity6111 measurement in @entity1 . Our study demonstrates strong agreement between the blood spot and the venous GFR with acceptable bias, precision and diagnostic accuracy, especially in @entity1 with GFR < 60 mL/ @entity1009 .73 m(2).
