What is Serum Creatinine

Serum Creatinine is mainly produced by the decomposition and metabolism of muscle creatine of human body. Therefore it is closely related with total muscles amount and seldom affected by diet; tiny amount of serum creatinine comes from digestive protein in human body, having tiny influence on serum creatinine. Serum creatinine is one of the most significant indexes of renal function injury in clinical practice.

Clinical meaning of serum creatinine:

Serum creatinine is a normal metabolic waste of human body, excreted out of human body after filtrated by glomerulus. Generally, normal value of serum creatinine for healthy adult is 44-133 umol / L (0.5~1.5 ml / L). When glomerulus filtrating function is normal, fasting serum creatinine keeps stable, which means less than 133umol / L. This indicator is usually applied in clinical practice to make a preliminary judgment of glomerulus filtration function.

Serum creatinine test is an important indicator to diagnose Renal Failure and it is seldom affected by diet, so serum creatinine can reflect glomerulus function better than blood urea nitrogen. However, normal serum creatinine does not mean ordinary glomerulus filtration function. In other words, serum creatinine can be normal in Renal Insufficiency Compensatory Stage. Serum creatinine increases until renal function losses 70%. Therefore, serum creatinine is not an accurate indicator to judge renal function damage and glomerulus filtrating rate in early stage. One point is certain that once serum creatinine increases, this disease has already developed into Renal Insufficiency. Clinically, serum creatinine value is usually used to judge the severity of renal function.

When serum creatinine is less than 186 umol / L, it is Renal Insufficiency Compensatory Stage; when 186-442 umol / L, it is Renal Insufficiency Decompensatory Period; when 442-707 umol / L, it is Renal Failure; when more than 707umol / L, it is Uremia period.


Therefore, serum creatinine testing has great clinical significance of diagnosing renal failure and observe illness condition as well as prognosis.