Total vs. Separate Kidney Function: The Limitations of Creatinine
Serum Creatinine and Kidney Function The kidneys help filter waste products (such as urea and creatinine) from the body. Serum creatinine is the amount of creatinine in the blood, which is mainly produced from muscle metabolism. When kidney filtering capacity decreases, the level of creatinine in the blood rises. Therefore, serum creatinine is used as a general indicator of the overall kidney function (glomerular filtration rate or GFR). However, serum creatinine only reflects total kidney function. It does not provide information about how much each kidney is functioning separately. For example, if one kidney is functioning well and the other is impaired, the total creatinine may appear nearly normal, but the problem in the diseased kidney may not be detected. To determine the individual function of each kidney , special imaging tests are required, such as: Dynamic renal scan (DTPA or MAG3 scan) → evaluates each kidney’s function separately. Renogra...