Understanding Creatinine (CRET) in Kidney Health: What You Need to Know

Creatinine (CRET) is an important, non-calculated value relating to kidney function. Creatinine is a nitrogenous waste produced by the cells during the course of muscle activity. It is referred to on lab sheets as "cret", "cre", "CR", and "creat".

Normal Kidney Function

• Creatinine is normally filtered out of the blood by the kidneys. However, when kidney function is impaired, creatinine levels remain high.

Application

• Since creatinine levels remain relatively steady, they are a good marker for impaired kidney function. Sometimes doctors also measure creatinine clearance, the rate at which creatinine is cleared from the blood by the kidneys.

Important Fact

• It is important to remember that creatinine does not cause kidney function to decrease. It merely indicates that function is not normal.

Misconceptions

• Don't confuse creatinine with creatine. Creatine is another nitrogenous waste product that is similar to creatinine. However, it is not a measure of kidney function.

Warning

• Don't confuse serum creatinine with urine creatinine. Serum creatinine is the indicator of kidney function. Urine creatinine is used to calculate the protein-to-creatinine ratio, which is one way to measure urine protein in kidney disease.