Serum creatinine: advantages and pitfalls
Serum creatinine (sCr) is today the most commonly used marker to estimate glomerular filtration rate (GFR). However, measuring and interpreting creatinine is not so simple. Some physiological reasons, particularly its dependence on muscle mass makes sCr an imperfect biomarker of GFR. However, there are also analytical reasons that could be further improved. The implementation of ID-MS traceable creatinine assays (enzymatic and compensated Jaffe) improved estimation of GFR by reducing bias. Enzymatic methods which are more precise and less susceptible to interfere with non-creatinine chromogens than compensated Jaffe methods, provide more reliable estimations of GFR.