Creatinine Blood Test: What is it and What is it Used For?

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A creatinine blood test is a standard blood test used to check how much creatinine is in the blood. Creatinine can be a great indicator of how well the kidneys are functioning. When creatinine levels are elevated it often indicates that that the kidneys are either malfunctioning or failing. Adult males are considered to have normal blood creatinine levels at 0.6 to 1.2 milligrams per deciliter. Females are considered to have normal blood creatinine levels at 0.5 to 1.1 milligrams per deciliter.

When is this Test Performed?

This blood test is often ordered during a patient’s yearly physical exam to check on how well their kidneys are functioning. This test may also be ordered when a patient is acutely ill or when a doctor suspects kidney problems. The following symptoms often lead to a doctor performing a creatinine blood test: fatigue, loss of appetite, difficulty sleeping, concentration problems, decreased output of urine, trouble urinating, urinating more often, high blood pressure, pain in the mid-back, brown or foamy urine, blood in the urine, and swelling of the eyes, ankles, face, thighs, abdomen or wrists. These symptoms often indicate kidney dysfunction therefore this blood test will be performed to diagnose the problem or to rule out kidney dysfunction as the cause.

What do the Results Mean?

Several different kidney conditions can cause elevated creatinine levels. An elevated level may indicate that the kidneys blood vessels are swollen due to an autoimmune disease or an infection. It can indicate that the kidneys are affected by a bacterial infection. It can indicate that some of the small tubes in the kidneys have dead cells. It can indicate a kidney stone. Elevated levels may also indicate a decrease in blood flow to the kidneys caused by diabetes complications, shock, atherosclerosis, congestive heart failure or dehydration.

How is this Test Performed?

This blood test is simple and painless. A healthcare professional will use a tourniquet and tie it about one inch above the elbow. They will then insert a venipuncture needle or a butterfly needle. They will then connect the blood collection tube to the needle and draw the blood. Once they have enough blood they will release the tourniquet, remove the needle and place a bandaid to the needle prick.

Causes of Elevated Creatinine Levels

All conditions that adversely affect the kidneys will result in high levels of creatinine. Diabetes mellitus and high blood pressure are the most common conditions that often lead to longstanding kidney disease. Certain drugs can cause creatinine levels to be abnormally high. Another cause of elevation is eating a lot of dietary meat. This elevation typically occurs almost immediately after ingestion.


Lab Tests Online. (2009). Creatinine. Retrieved on September 25, 2009 from Website: