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Diagnostic Tests

Blood Test: Basic Metabolic Panel

What’s a Basic Metabolic Panel?

A basic metabolic panel (BMP) is a blood test that gives doctors clues about how the body is working. Doctors usually order this as part of a routine physical or as a way to help diagnose a medical problem.

Although the basic metabolic panel tests for several different things, you should only need to get blood taken once. The lab uses the same blood sample to run all the tests.

The BMP test looks at:

  • Glucose. The body uses this type of sugar for energy. Abnormal glucose levels can indicate diabetes or hypoglycemia (low blood sugar).
  • Calcium. This mineral plays an important role in muscle contraction, transmitting messages through the nerves, and the release of hormones. Elevated or decreased calcium levels may be a sign of a hormone imbalance or problems with the kidneys, bones, or pancreas.
  • Sodium, potassium, carbon dioxide, and chloride. These electrolytes help balance the body’s fluid levels, among other things. They also play a role in regulating heart rhythm, muscle contraction, and brain function. Abnormal levels of these electrolytes may be a sign of heart disease, kidney disease, or dehydration.
  • Blood urea nitrogen (BUN) and creatinine. These waste products are filtered out of the blood by the kidneys. High levels in the blood may be a sign that the kidneys aren’t working as well as they should.


In an emergency, the basic metabolic panel can be done without any special preparation. But the results are more accurate when a person has been fasting. So your doctor may ask you not to eat or drink for 8 to 12 hours before having your blood taken.

You should tell your doctor about any medications you’re taking (including over-the-counter medicines or herbal supplements) because certain drugs might alter the test results.

It can help to wear a T-shirt or other short-sleeved top on the day of the test to make things faster and easier for the technician who will be drawing the blood.

The Procedure

A health professional will usually draw the blood from a vein in your arm — most often on the inside of the elbow, but sometimes on the back of the hand. The technician cleans the skin surface with antiseptic and ties an elastic band (tourniquet) around the upper arm so the veins swell with blood and are easy to see.

Next, it’s time for the needle. It should feel like a quick pinprick. Occasionally, it can be hard to find a vein so a nurse, doctor, or technician may need to try more than once. That’s not the norm, though — most people’s veins are easy to find.

It’s best to try to relax and stay still during the procedure since tensing muscles can make it harder and more painful to draw blood. And if you don’t want to watch the needle being inserted or see the blood collecting, you don’t have to. Look the other way and maybe relax by focusing on saying the alphabet backwards, doing some breathing exercises, thinking of a place that makes you happy, or listening to your favorite music.

The technician will draw the blood so it collects in a vial or syringe. Collecting blood will only take a few minutes. Once the technician has enough blood, he or she removes the needle and covers the area with cotton or a bandage to stop the bleeding. After the test, you may notice some bruising — that’s normal and it should go away in a few days. Don’t be afraid to ask the technician if you have any questions about the blood draw.


A blood test is a safe procedure and there are no real risks. Some people may feel faint or lightheaded during a blood test. And, while nobody really loves needles, a few teens have a strong fear of them. If that’s you, talk to your doctor since there are ways to make the procedure easier for you.


The blood sample will be processed by a machine. It usually only takes a few hours or a day or so for your doctor to get the results. If your doctor has any concerns after the test results are in, he or she may want to do additional tests.

Reviewed by: Yamini Durani, MD
Date reviewed: August 2014