Development of a modified sampling and calculation method for isotope plasma clearance assessment of the glomerular filtration rate in patients with cirrhosis and ascites

摘要

I read with much interest the paper published by Wickham et al. [1]. Indeed, an accurate radionuclide method for measuring renal clearance in patients with ascites is still missing.However, the design of the study is surprising. As mentioned by the guidelines, the only accepted method in this type of patients is the comparison between urine and plasma samples, because one avoids the problems of additional spaces of distribution. The authors claim that this method is inaccurate, although many others such as Brochner-Mortensen J., Chantler C, Klassen D.K., and Otto A.G. have used this method as the reference for testing simplified methods. However, I do not deny the technical difficulties related to the method, such as the need for multiple long periods of urine collection. The authors, having eliminated the urine method, consider in their introduction that 'there is no widely agreed mathematical model of plasma clearance in the presence of ascites and oedema'.