Creatinine

Intended Use

Biostep Diagnostic’s creatinine reagent is intended for the in-vitro quantitative diagnostic determination of creatinine in human serum or urine on both automated and manual systems.

Background

Creatinine is synthesized in kidney, liver and pancreas. It is transported in blood to other organs such as muscle and brain where it is phosphorylated to phosphocreatine. Some free creatine in muscle is converted to creatinine daily and the amount of creatinine produced is proportional to muscle mass. In the absence of renal disease, excretion rate of creatinine in an individual is relatively constant. Therefore, measurement of creatinine clearance is useful in detecting renal disease and estimating the extent of impairment of renal function. Both serum creatinine and urea levels are elevated in patients with renal malfunction especially decreased glomerular filtration. In the early stage of kidney damage, increase in serum urea level usually precedes the increase in serum creatinine. However serum urea levels may be affected by dehydration, diet and protein metabolism. On the other hand, serum creatinine levels tend to be constant and unaffected by such factors. Thus serum creatinine is a significantly more reliable renal function screening test than serum urea.