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Category Archives: Nephrology

Renal Handling of Urea


Renal Handling of Urate Urate, an anion that is the base form of uric acid, provides a fascinating example of the renal handling of organic anions that is particularly important for clinical medicine and is illustrative of renal pathology. An increase in the plasma concentration of urate can cause gout and is thought to be […]

Ammonia and Urea Cycle


Ammonia (NH3) is a small metabolite that results predominantly from protein and amino acid degradation. It is highly membrane-permeant and readily crosses epithelial barriers in its nonionized form. Ammonia does not have a physiologic function. However, it is important clinically because it is highly toxic to the nervous system. Because ammonia is being formed constantly […]

Evaluation of Renal Function


Assessment of kidney function using both qualitative and quantitative methods is an important part of the evaluation of patients and an essential characterization of individuals who participate in clinical research investigations. Estimating of creatinine clearance has been considered the clinical standard for assessment of kidney function for nearly 50 years, and continues to be used […]

Creatinine Clearance Estimation – Non-Steady State


Using non-steady-state serum creatinine values to estimate creatinine clearance is difficult, and a number of approaches have been proposed. The author use Equation 1 below to estimate creatinine clearance when steady-state conditions have not been achieved. ClCr (mL/min) = { (Production of Creatinine in mg/day) – [(SCr 2 – SCr 1)(V Cr) / t]*(10 dL/L)} […]

Creatinine Clearance Estimation – Steady State


Different from most drug administration regimens, creatinine is constantly produced and released into plasma by the body muscle mass. Because many drugs are partially or totally eliminated by the kidney, an accurate estimation of renal function is an important component in the application of pharmacokinetics to designing drug therapy regimens. Creatinine clearance as determined by […]