Creatinine Lab
Title: Creatinine Assay
Aim: To determine the creatinine clearance of a selected undiluted urine samples by graphical extrapolation from a creatinine curve.
Materials and Apparatus:
University of the West Indies: Department of Basic Medical Sciences
Laboratory Manual: BC35A, Creatinine Assay, pages 6-8, 2012
Changes to the Method:
The experiment utilized one undiluted urine samples for concentration determination instead of five aliquots of twenty four hour urine samples. The urine sample and standard creatinine solutions were analyzed spectrophotometrically approximately five minutes after they were made up instead of using the allotted time interval (minutes) as suggested by the laboratory manual.
Results:
Please see attachments.
Discussion
Creatinine is a chemical waste molecule that is generated from muscle metabolism. It is an anhydride of creatine, the end product of phosphocreatine metabolism; measurements of its rate of urinary excretion are used as diagnostic indicators of kidney function and muscle mass.The experiment utilized serum creatinine.Creatinine is filtered out of the blood by the kidneys (glomerular filtration). There is little tubular reabsorption of creatinine. If the filtering of the kidney is deficient, creatinine blood levels rise. Therefore, creatinine levels in blood and urine may be used to calculate the creatinine clearance which reflects the glomerular filtration rate (GFR).The GFR is clinically important because it is a measurement of renal function .A more complete estimation of renal function can be made when interpreting the blood (plasma) concentration of creatinine along with that of urea. BUN-to-creatinine ratio (the ratio of blood urea nitrogen to creatinine) can indicate other problems besides those intrinsic to the kidney; for example, a urea level raised out of proportion to the creatinine may indicate a pre-renal problem such as volume depletion. The typical human reference ranges for serum creatinine are
Aim: To determine the creatinine clearance of a selected undiluted urine samples by graphical extrapolation from a creatinine curve.
Materials and Apparatus:
University of the West Indies: Department of Basic Medical Sciences
Laboratory Manual: BC35A, Creatinine Assay, pages 6-8, 2012
Changes to the Method:
The experiment utilized one undiluted urine samples for concentration determination instead of five aliquots of twenty four hour urine samples. The urine sample and standard creatinine solutions were analyzed spectrophotometrically approximately five minutes after they were made up instead of using the allotted time interval (minutes) as suggested by the laboratory manual.
Results:
Please see attachments.
Discussion
Creatinine is a chemical waste molecule that is generated from muscle metabolism. It is an anhydride of creatine, the end product of phosphocreatine metabolism; measurements of its rate of urinary excretion are used as diagnostic indicators of kidney function and muscle mass.The experiment utilized serum creatinine.Creatinine is filtered out of the blood by the kidneys (glomerular filtration). There is little tubular reabsorption of creatinine. If the filtering of the kidney is deficient, creatinine blood levels rise. Therefore, creatinine levels in blood and urine may be used to calculate the creatinine clearance which reflects the glomerular filtration rate (GFR).The GFR is clinically important because it is a measurement of renal function .A more complete estimation of renal function can be made when interpreting the blood (plasma) concentration of creatinine along with that of urea. BUN-to-creatinine ratio (the ratio of blood urea nitrogen to creatinine) can indicate other problems besides those intrinsic to the kidney; for example, a urea level raised out of proportion to the creatinine may indicate a pre-renal problem such as volume depletion. The typical human reference ranges for serum creatinine are
References: 1. Delanghe J; De Slypere JP, De Buyzere M, Robbrecht J, Wieme R, Vermeulen A (Aug 1989). "Normal reference values for creatine, creatinine, and carnitine are lower in vegetarians". Retreived October 3, 2012. 2. "The creatine-creatinine equilibrium. The apparent dissociation constants of creatine and creatinine.Retrieved October 3, 2012. 3. "International Society of Sports Nutrition position stand: creatine supplementation and exercise". October 3, 2012.