Blood chemistry tests

Blood chemistry tests measure the amount of electrolytes, fats, proteins, sugar, and enzymes in your blood.

These tests help your doctor see how well certain organs, such as the liver and kidneys, are working. The results can also show your doctors how a cancer treatment is affecting your body.

How blood chemistry tests work

Your healthcare team may perform a blood chemistry test in your doctor’s office or they may refer you to a lab to have it done.

For the test, a healthcare professional draws a blood sample with a needle. Usually, the sample is taken from a vein on the inside of your elbow.

In some cases, blood may be taken from veins in the wrist or the back of the hand.

If you are undergoing chemotherapy and have a port, blood can be drawn from the port for testing. A port is a small device placed under your skin that allows your healthcare team to deliver chemotherapy through a vein in your chest.

Types of blood chemistry tests

Here are some examples of blood chemistry tests used during breast cancer diagnosis and treatment:

Basic metabolic panel (BMP). This test measures eight substances in your blood. It checks:

• Your hydration
• How your body uses food as energy (metabolism)
• How well your kidneys work

Comprehensive metabolic panel (CMP). This test measures 14 substances in your blood. It checks:

• Some of the BMP levels mentioned above
• The balance of natural chemicals in your body, including:
• Liver enzyme levels, which give your doctor information about how well your liver is working

Electrolyte panel. Electrolytes are certain minerals we get from the food we eat and fluids we drink. Electrolytes help keep many body processes balanced.

Examples of electrolytes include calcium, potassium, and sodium. Electrolyte panels check the levels of the body’s main electrolytes to make sure they aren’t too low or too high.

Who gets blood chemistry tests?

Blood chemistry tests are common in checking your health. You may have had them for annual physical exams in the past, or when you’ve had signs of illness.

These tests are a standard part of diagnosis and treatment for breast cancer. This is because many cancer treatments are broken down in the kidneys or liver, and blood chemistry test results can tell your doctor if your body is handling treatment well. If the body is not handling treatment well, your doctor can adjust the dose of your medicine or switch you to a new one.

Why are blood chemistry tests important?

Each substance measured by a blood chemistry test has a normal range. Results in the normal range mean that your organs or body functions are working as they should. Results outside of the normal range can be a sign of a problem.

In breast cancer, blood chemistry tests are used to:

• Make sure certain cancer medicines are a safe choice for you
• Monitor how treatment side effects are affecting you
• Look for any signs that the cancer may have traveled to another part of the body

Abnormal test results can lead to more blood tests or imaging tests. They can also lead to changes in your treatment. For example:

• If a result suggests your heart or kidneys aren’t working well, certain cancer treatments might not be safe for you.
• If results show changes in calcium levels, your healthcare team may recommend bone scans to look for cancer in the bones.

Visit the Testing page to learn about other tests that guide diagnosis and treatment.