Creatinine

What the risks are:

• excessive bleeding
• fainting or feeling lightheaded
• hematoma (blood accumulating under the skin)
• infection (a slight risk any time the skin is broken)
• multiple punctures to locate veins

Why is the test performed
A measurement of the serum creatinine level is used to evaluate kidney function.

Creatinine is a breakdown product of creatine, which is an important constituent of muscle. Creatinine can be converted to the ATP molecule, which is a high-energy source. The daily production of creatine and subsequently creatinine, depends on muscle mass, which fluctuates very little.

Creatinine is excreted from the body entirely by the kidneys. With normal renal excretory function, the serum creatinine level should remain constant and normal.

Special considerations:

Drugs that can increase creatinine measurements include aminoglycosides (for example, gentamicin), cimetidine, heavy metal chemotherapeutic agents (for example, Cisplatin), and nephrotoxic drugs such as cephalosporins (for example, cefoxitin).