Serum or Plasma Creatinine Concentration (Standard Method)

Why This Test Matters

Creatinine is a byproduct of muscle metabolism that your kidneys filter out of your blood. High levels can indicate poor kidney function, while low levels might suggest dehydration or other conditions. This test is often used alongside other measures to monitor kidney health, especially in people with diabetes, high blood pressure, or a family history of kidney disease.

What to Expect Before the Test

You may be asked to fast for a few hours before the test, but this depends on your doctor’s instructions. If you’re taking certain medications (like some pain relievers or diuretics), let your healthcare provider know. Avoid strenuous exercise or heavy meals 24 hours before testing.

During the Test

A healthcare professional will draw blood from a vein in your arm. You may feel a slight pinch, but it usually takes only a few minutes. If you’re nervous, let your provider know—they can take steps to make it more comfortable.

After the Test

You can resume your normal activities right after. There’s usually no downtime, but watch for signs of bruising, swelling, or excessive bleeding at the injection site. If you experience dizziness or lightheadedness, rest for a few minutes.