A BMP is a blood test that measures eight different chemicals that occur naturally in the blood. It can inform doctors about electrolytes, fluid balance, glucose levels, and other markers of a person’s health.

This article discusses a BMP, its uses, why a person may need it, and what happens during the test. It also considers the risks, results, and how it compares with a comprehensive metabolic test (CMP).

A healthcare professional drawing blood from a female patient during a blood test.Share on Pinterest
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A BMP is a blood test that provides doctors with information about the body’s levels of electrolytes, fluid balance, and kidney function.

Healthcare workers usually perform these tests on the plasma part of the blood.

The test measures eight different chemicals in the blood:

  • Electrolytes: Carbon dioxide, sodium, potassium, and chloride. These electrically charged minerals help control the balance of acids and bases and the level of fluids in the body.
  • Calcium: This is an essential mineral that helps keep the heart, nerves, and muscles functioning properly.
  • Glucose: The body’s main energy source.
  • Blood urea nitrogen (BUN) and creatinine: These are waste products that the kidneys remove from the body.

This test is also known as a chemistry screen, chemistry panel, chem 7, or electrolyte panel.

A doctor can use a BMP to check various body functions. These include:

A doctor may perform a BMP as part of a regular health checkup. A person may also need a BMP if a doctor monitors them for particular chronic conditions, such as kidney disease or high blood pressure, or if doctors treat them in an emergency room.

If a person has abnormal levels of any of the eight substances in a BMP test, they may be at risk of a serious health issue.

A person will experience the following during a BMP blood test:

  1. A healthcare professional, such as a doctor or nurse, will insert a small needle into a vein in a person’s arm.
  2. They will collect a blood sample into a vial or test tube, which typically takes less than 5 minutes and may cause a slight stinging feeling.
  3. The healthcare professional will send the blood sample to a lab for analysis.

What happens after the test?

After the healthcare professional has drawn a blood sample, they will remove the needle and may place a small bandage or piece of cotton wool over the injection site to stop any bleeding.

A person may have slight bruising or tenderness where the needle entered the skin, but symptoms usually resolve quickly.

A laboratory machine will process the test results for the lab technicians and doctors to analyze. If the results of the test show abnormalities, the doctor may order further tests to diagnose the issue.

How can people prepare for the test?

A person may need to stop eating or drinking for 8 hours before the test.

To make it easier to access the injection site, people should wear short-sleeved shirts or T-shirts to their appointment. They should also discuss any medications they are currently taking and any recent illnesses with the doctor.

Learn more about fasting before blood tests.

Risks for a blood test are minimal. An individual may experience slight bruising or a little pain at the injection site, but these symptoms typically go away quickly. Some people may feel faint for a little while after the test.

BMP results will become available after analysis at a laboratory, which can take a few days.

If a BMP reveals that a person has abnormal levels of any of the chemicals measured, it could indicate various medical conditions. These include:

Following abnormal results, a doctor may order further tests to determine what is affecting the person and how best to treat them.

Learn more about how long it takes to receive blood test results.

Healthy ranges

This chart shows the ranges for the different chemicals tested during a BMP, according to the American Board of Internal Medicine (ABIM).

TestNormal rangePurpose
glucose70–99 mg/dLblood sugar levels
BUN8–20 mg/dL kidneys
creatininefemale: 0.5–1.1 mg/dL
male: 0.7–1.3 mg/dL
carbon dioxide (CO2)23–30 mEq/Lelectrolytes
chloride98–106 mEq/Lelectrolytes
potassium3.5–5.0 mEq/Lelectrolytes
sodium136–145 mEq/Lelectrolytes
calcium8.6–10.2 mg/dLmineral


  • mg = milligram
  • mmol = millimole
  • mEq = milliequivalents
  • L = liter
  • dL = deciliter = 0.1 liter

A complete or comprehensive metabolic panel (CMP) is similar to a BMP, except it measures 14 substances instead of eight in the blood.

Alongside the eight chemicals a BMP measures, a CMP also looks at levels of:

A doctor may favor a CMP over a BMP in cases where they believe the person may have a liver or kidney condition, or to monitor the effects of certain medications. A CMP may also be part of a regular checkup.

A person can discuss whether a BMP would be appropriate with a healthcare professional. Otherwise, a doctor may suggest a BMP to help evaluate a person’s health status.

Here are some answers to common questions about BMPs.

Should people fast for a basic metabolic panel test?

Sometimes, a healthcare professional may ask a person to avoid eating or drinking for 8 hours before the test.

A doctor will inform a person if they need to fast.

Is it concerning to have an abnormal BMP test result?

Abnormal results could be due to various reasons, including side effects of medicines. The doctor will discuss the results of each test with the individual and may perform or order further tests to determine what is affecting them.

A basic metabolic panel (BMP) refers to a group of blood tests measuring the levels of eight substances in the blood. The tests can provide doctors with information about the body’s levels of electrolytes, fluid balance, and kidney function.

Abnormal levels of any of these substances could indicate various health issues, such as issues with the kidneys, breathing, or glucose levels.

Individuals can receive a BMP as part of their regular checkup or if a doctor orders the test while diagnosing a health condition. The test is quick and has minimal risk.

If a BMP reveals abnormal results, a doctor may order further tests to help them diagnose and treat an illness.