| Creatinine |
Articles about Creatinine |
Information AboutCreatinine |
| CATEGORIES ABOUT CREATININE | |
| metabolism | |
| renal physiology | |
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PHYSIOLOGY It is mainly filtered by the kidney, though a small amount is actively secreted. There is some tubular reabsorption of creatinine, but this is compensated by a roughly equivalent degree of tubular secretion. If the filtering of the Kidney is deficient, blood levels rise. This effect is used as an indicator of Renal Function . However, in cases of severe renal dysfunction, the creatinine clearance rate will be ''overestimated'' because the active secretion of creatinine will account for a larger fraction of the total creatinine cleared. Men tend to have higher levels of creatinine because they have more Skeletal Muscle than women. DIAGNOSTIC USE Measuring serum creatinine is a simple test and it is the most commonly used indicator of renal function. A rise in blood creatinine levels is observed only with marked damage to functioning nephrons; therefore this test is not suitable for detecting early Kidney Disease . A better estimation of kidney function is given by the Creatinine Clearance test. Creatinine Clearance can accurately be calculated using serum creatinine concentration and some or all of the following variables: sex, age, weight,and race as suggested by the National Diabetes Association without a 24 hour urine collection ref" class="copylinks" target="_blank">Diabetes Care 2005 28(1):164-176 . Some laboratories will calculate the ClCr if written on the prescription; and, the necessary age, sex, and weight are included in the patient information. INTERPRETATION In the United States , creatinine is typically reported in 0.7 - 1.5 mg/dL, while in Canada and Europe μmol / Liter may be used. 1 mg/dL of creatinine is 88.4 μmol/l. The typical Reference Range for women is considered 0.5 to 1.0 mg/dL (about 45-90 μmol/l), for men 0.7 to 1.2 mg/dL (60-110 μmol/l). While a baseline serum creatinine of 2.0 mg/dL (150 μmol/l) may indicate normal kidney function in a male body builder, a serum creatinine of 0.7 mg/dL (60 μmol/l) can indicate significant renal disease in a frail old woman. More important than absolute creatinine level is the trend of serum creatinine levels over time. A rising creatinine indicates kidney damage, while a declining creatinine level indicates improving kidney function. |
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