ANURBF

• Exogenous Clearance Tests involve the use of substances that are not inherently produced by the body and require the administration of substances via invasive procedures.
• Inulin Clearance is the reference or gold standard method for clearance tests but is not currently used as a routine method for GFR testing and is used for research purposes.
• Radioisotopes involve the administration of radionucleotides such as 125I-iothalamate for determining glomerular filtration through the plasma disappearance of the radioactive material and enabling the visualization of the filtration in one or both kidneys.
• Calculated Glomerular Filtration Estimates are based on the serum creatinine without the urine creatinine.
• Cockcroft and Gault is the most frequently used formula used to document eligibility for reimbursement by the Medicare End Stage Renal Disease Program and is used to evaluate patient placement on kidney transplant lists.
• Modification of Diet in Renal Disease (MDRD) System utilizes additional variables and does not include body weight.
• Schwartz and Modified Counahan Barret Formula is a formula used for children.
• Tubular Reabsorption/Concentration Tests are performed in the laboratory.
• Fishberg involves measuring urine specific gravity after a 24-hour fluid deprivation.
• Mosenthal involves a volume and specific gravity comparison of day and night urine samples.
• Osmolarity Based on Colligative Properties involves measuring the osmolality of a solution.
• Freezing Point Osmometers use the principle that 1 mol solute will lower the freezing point by 1.86oC.
• Vapor Pressure Osmometers involve dew point determination and use microsamples of less than 0.1 Ml.
• Tubular Secretion and Renal Blood Flow Tests involve substances that are secreted by the tubular cells rather than filtered through the glomerulus.
• P-Aminohippuric Acid Test involves a non-toxic substance loosely bound to plasma proteins and measured in the peritubular capillaries.
• Phenolsulfonphthalein Test involves measuring renal blood flow.
• Titrable Acidity and Urinary Ammonia involves measuring acid urine and requires a sample of fresh or toluene-preserved urine collected at 2-hour intervals.
• Indigo CarmineTest involves the use of 100 mg indigo carmine.