|
In medicine (nephrology) renal function is an indication of the state of the kidney and its role in physiology. Medicine on the Web NLM (National Library of Medicine, contains resources for patients and healthcare professionals) Virtual Hospital (digital health sciences library by the University of Iowa) Online Medical Information- medical news, links and resources. ...
Nephrology is the branch of internal medicine dealing with the study of the function and diseases of the kidney. ...
Human kidneys viewed from behind with spine removed The kidneys are bean-shaped excretory organs in vertebrates. ...
Physiology (in Greek physis = nature and logos = word) is the study of the mechanical, physical, and biochemical functions of living organisms. ...
Indirect markers Most doctors use creatinine, urea and electrolytes to determine renal function. These measures are adequate to determine whether a patient is suffering from kidney disease. Creatinine is a breakdown product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body (depending on muscle mass). ...
Urea is an organic compound of carbon, nitrogen, oxygen and hydrogen, with the formula CON2H4 or (NH2)2CO. Urea is also known as carbamide, especially in the recommended International Non-proprietary Names (rINN) in use in Europe. ...
An electrolyte is a substance which dissociates free ions when dissolved (or molten), to produce an electrically conductive medium. ...
See the article on the kidney for the anatomy and function of healthy kidneys and a list of diseases involving the kidney. ...
Unfortunately, BUN and creatinine will not be outside the normal range until 60% of total kidney function is lost. Hence, creatinine clearance is a more accurate measure and is used whenever renal disease is suspected or careful dosing of nephrotoxic drugs is required.
Glomerular filtration rate In renal patients, the glomerular filtration rate (GFR) is used. This is calculated by comparing urine creatinine levels with the blood test results. It gives a more precise indication of the state of the kidneys. The GFR is expressed in ml/min. For most patients, a GFR over 60 ml/min is adequate. But, if the GFR has significantly declined from a previous test result, this can be an early indicator of kidney disease requiring medical intervention. The sooner kidney dysfunction is diagnosed and treated, the greater odds of preserving remaining nephrons, and preventing the need for dialysis. The equation is very easy to use on various medical or kidney web sites. Some allow the calculator to be down-loaded onto your computer or PDA. Very often, the GFR is expressed as ml/min/1.73 m2. This is an indication that the GFR needs to be corrected for the body surface area (BSA). While most adults have a BSA that approaches 1.7 (1.6-1.9), extremely obese or slim patients should have their GFR corrected for their actual BSA. Glomerular filtration rate (GFR) is the volume of fluid filtered from the renal glomerular capillaries into Bowmans capsule per unit time. ...
Urine is liquid waste excreted by the kidneys and is produced by the process of filtration. ...
Creatinine is a breakdown product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body (depending on muscle mass). ...
Blood tests are laboratory tests done on blood to gain an appreciation of disease states and the function of organs. ...
The millilitre (spelled milliliter in American English and German) is a metric unit of volume that is equal to one thousandth of a litre. ...
This article contains information that has not been verified. ...
In physiology and medicine, the body surface area (BSA) is the measured or calculated surface of a human body. ...
BSA can be calculated on the basis of weight and height.
Cockroft-Gault formula A commonly used surrogate marker for actual creatinine clearance is the Cockroft-Gault formula, which employs creatinine measurements and a patient's weight to predict the clearance. The calculator can be found/used or down-loaded from various medical or kidney web sites. It is very easy to calculate and healthcare providers frequently have the calculator on their PDAs. The formula, as originally published, is: Creatinine clearance is a method that estimates the glomerular filtration rate (GFR) of the kidneys. ...
Creatinine is a breakdown product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body (depending on muscle mass). ...
In medicine, the clearance, also renal clearance or renal plasma clearance (when referring to the function of the kidney), of a substance is the inverse of the time constant that describes its removal rate from the body divided by its volume of distribution (or total body water). ...
This formula expects weight (actually mass) to be measured in kilograms and creatinine to be measured in mg/dL, as is standard in the USA. The resulting value is multiplied by a constant of 0.85 if the patient is female. This formula is useful because the calculations are relatively simple and can often be performed without the aid of a calculator. The international prototype, made of platinum-iridium, which is kept at the BIPM under conditions specified by the 1st CGPM in 1889. ...
A modern basic arithmetic calculator A calculator is a device for performing numerical calculations. ...
A modification of this formula, useful for the common units of measure, is:
This formula uses metric units (weight in kilograms, creatinine in µmol/L). The constant is 1.23 for men and 1.04 for women. The international prototype, made of platinum-iridium, which is kept at the BIPM under conditions specified by the 1st CGPM in 1889. ...
It is named after the scientists who first published the formula (Cockroft & Gault, 1976).
==MDRD formula The most recently advocated formula for calculating the GFR is the one that was developed as a result of the Modification of Diet in Renal Disease (MDRD) study (Levey et al 1999). Although Levey developed it in 1999, national kidney and diabetes foundations are educating patients and healthcare providers of the tools available to detect and treat kidney disease earlier. This equation can be found and utilized on the internet. You do not need to know math. WebMD is a good resource. For creatinine in mg/dL
For creatinine in µmol/L
The constant is 1 for a white male, and is multiplied with 0.742 for females and multiplied with 1.21 for African Americans.
Creatinine levels in µmol/L can be converted to mg/dL by dividing them by 88.4.
A more elaborate version of the MDRD equation also includes albumin and blood urea nitrogen levels. You may be looking for albumen, or egg white. ...
The blood urea nitrogen (BUN) test is a measure of the amount of nitrogen in the blood that comes from urea. ...
Children: Schwartz In children, the Schwartz formula is used. This employs the serum creatinine, the child's height and a constant to estimate the creatinine clearance. An online calculator[1] warns that the result may overstate the GFR. Creatinine is a breakdown product of creatine phosphate in muscle, and is usually produced at a fairly constant rate by the body (depending on muscle mass). ...
k - the constant is 0.33-0.45 in infants, 0.55 in children or adolescent girls, or 0.70 in adolescent boys.
References - Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron. 1976;16(1):31-41. PMID 1244564
- Levey AS, Bosch JP, Lewis JB, Greene T, Rogers N, Roth D. A more accurate method to estimate glomerular filtration rate from serum creatinine: a new prediction equation. Modification of Diet in Renal Disease Study Group. Ann Intern Med 1999;130:461-470. PMID 10075613.
See also In medicine, the clearance, also renal clearance or renal plasma clearance (when referring to the function of the kidney), of a substance is the inverse of the time constant that describes its removal rate from the body divided by its volume of distribution (or total body water). ...
Creatinine clearance is a method that estimates the glomerular filtration rate (GFR) of the kidneys. ...
Kt/V - a dimensionless number used to quantify hemodialysis and peritoneal dialysis treatment adequacy. ...
Pharmacokinetics is a branch of pharmacology dedicated to the study of the time course of substances and their relationship with an organism or system. ...
The renal clearance ratio is found with the following equation: X is the analyte substance Cx is the renal plasma clearance of X Cin is the renal plasma clearance of inulin. ...
Standardized Kt/V, also std Kt/V, is a way of measuring (renal) dialysis adequacy. ...
The urea reduction ratio (URR), is a dimensionless number used to quantify hemodialysis treatment adequacy. ...
External links | 
Feeds |
Contact