Renal function: Estimation of glomerular filtration rate
The glomerular filtration rate (GFR) is widely accepted as the best overall measure of kidney function. American National Kidney Foundation guidelines define chronic kidney disease (CKD) by either a GFR of less than 60 mL/min/1.73 m2 or the presence of kidney damage, regardless of the cause, for 3 o...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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Society of Medical Biochemists of Serbia, Belgrade
2007-01-01
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| Series: | Journal of Medical Biochemistry |
| Subjects: | |
| Online Access: | https://scindeks-clanci.ceon.rs/data/pdf/1452-8258/2007/0354-34470701051D.pdf |
| Summary: | The glomerular filtration rate (GFR) is widely accepted as the best overall measure of kidney function. American National Kidney Foundation guidelines define chronic kidney disease (CKD) by either a GFR of less than 60 mL/min/1.73 m2 or the presence of kidney damage, regardless of the cause, for 3 or more months, and classify stages of CKD severity according to GFR. GFR can be measured as the urinary or plasma clearance of exogenous filtration markers such as inulin. However, because of difficulty in use, expenses and radiation exposure, these methods have limited use in the routine laboratories. Creatinine clearance may be a useful alternative when exogenous markers are not available, but timed urinary collection is not convenient for patients and is susceptible to error during collection. GFR is often estimated clinically from serum concentrations of endogenous creatinine or cystatin C. Serum cystatin C has not yet been adequately evaluated as an index of GFR, and serum creatinine is affected by the GFR and by factors independent of GFR, including age, sex, race, body size, diet, certain drugs and laboratory analytical methods. According to National Kidney Foundation clinical guidelines, clinical laboratories should report an estimated GFR calculated from prediction equations, in addition to reporting the serum marker value. The currently recommended estimating equation was developed from the Modification of Diet in Renal Disease (MDRD) study. This equation uses age, sex, race (African-American vs. non-African-American), and serum creatinine concentration, and does not require a body weight variable because it normalizes GFR for a standard body surface area of 1.73 m 2. To achieve improved accuracy of calculated GFR with this equation, it is recommended that commercial creatinine methods should be calibrated against certified reference material and should be traceable to IDMS (isotope dilution mass spectrometry) methodology. MDRD equation has been shown to be useful for CKD patients, but its use is still unclear for people with low values for serum creatinine and high values for GFR, including healthy individuals, children and pregnant women. Validation studies are in progress to evaluate the MDRD equation for other ethnic groups and various disease conditions. |
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| ISSN: | 1452-8258 1452-8266 |