Glomerular filtration rate measurement by “single-shot” injection of inulin

Abstract

In 14 ADPKD patients the total body clearance and the urinary clearance of inulin using the constant infusion method were compared with the "single-shot" technique. Triplicate measurements of both clearances by each infusion method were obtained in 12 out of 14 patients. A high correlation was found between the total body clearance and the urinary clearance for both the constant infusion method (r = 0.96) and the single injection technique (r = 0.96). The coefficient of variation for the total body clearance of inulin was significantly lower for the constant infusion method and the single injection technique (7.8% and 7.1%) than for the urinary clearance of inulin (11.3% vs. 9.7%, P < 0.05). A constant overestimation of the urinary clearance by the total body clearance was observed with both methods (constant infusion method 8.3 ml.min-1 x 1.73 m-2 and single injection technique 13.4 ml.min-1 x 1.73 m-2). No concentration-dependent clearance was present. Determination of plasma inulin, especially at low levels, showed substantial interference by glucose. We conclude that, taking into account a constant overestimate of urinary clearance by the total body clearance of inulin, the single injection total body clearance possesses the best reproducibility and shows a good agreement with the conventional urinary clearance, which can be calculated by: GFR = TBCLss-13.1 ml.min-1 x 1.73 m-2 (in the range of 28 to 124 ml.min-1 x 1.73 m-2).

Measured GFR as a Confirmatory Test for Estimated GFR

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Determination of the Glomerular Filtration Rate by Identification of Sinistrin Kinetics

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The effect of renal hyperfiltration on urinary inflammatory cytokines/chemokines in patients with uncomplicated type 1 diabetes mellitus

“…Plasma was separated, placed on ice and then stored at −70°C before the assay. Inulin and PAH were measured in serum by colorimetric assays using anthrone and N-(1-naphthyl) ethylenediamine, respectively [14][15][16]. The mean of two baseline clearance periods represents GFR INULIN and ERPF, expressed per 1.73 m 2 .…”

“…Renal blood flow (RBF) was derived using ERPF/(1−haematocrit) and renal vascular resistance (RVR) was derived by dividing the mean arterial pressure by the RBF. All renal haemodynamic measurements were adjusted for body surface area [14,16]. Upon arrival at the renal physiology laboratory, participants were asked to void and this final volume completed the 24 h urine collection.…”