About Our CMP Blood Test
Purpose of the test
The purpose of the CMP is to conduct a broad assessment of various aspects of physical well-being. With 14 measurements, it can detect a range of abnormalities in blood sugar, nutrient balance, metabolism, and liver and kidney health.
Depending on the situation, a CMP can be employed for the following reasons:
- Screening is used to identify health problems before symptoms occur. Thus often prescribed as part of a routine health checkup to identify any underlying conditions.
- Diagnosing the cause after symptoms have started
- Guide and monitor treatment for various diseases to determine how a patient’s condition may change over time and to detect any medication side effects, especially those that may affect the liver or kidneys.
What does the test measure?
The CMP includes 14 separate measurements performed on the same blood sample. Some laboratories also calculate additional ratios, such as the albumin-to-globulin (A/G) ratio or the BUN-to-creatinine ratio, to help interpret results.
- Alanine aminotransferase (ALT): an enzyme primarily found in the liver, and when elevated, indicates liver damage or disease.
- Albumin: a protein produced in the liver that transports important substances (hormones, vitamins, and enzymes) through the body and also keeps fluid from leaking out of blood vessels. Decreased albumin levels can indicate dehydration, kidney disease, or liver disease.
- Alkaline phosphatase (ALP): an enzyme produced in the liver and bones but also found in tissues throughout the body. Elevated levels suggest liver disease or a bone disorder. In women, ALP is produced by the placenta during pregnancy.
- Aspartate aminotransferase (AST): an enzyme mostly present in the liver, but also in the heart, kidneys, muscle, and other tissues of the body. AST is often performed when liver damage is present, such as alcoholic liver disease, viral hepatitis A, B, or C, diabetes, or certain metabolic disorders of the liver.
- Bicarbonate: an electrolyte that helps maintain the body’s acid-base balance. Most carbon dioxide in the blood is in the form of bicarbonate, and an abnormal level indicates an improper acid-base balance.
- Bilirubin: a waste product that is yellowish in color and is produced from the natural breakdown of aged red blood cells. The liver plays a central role in eliminating bilirubin from the body.
- Blood urea nitrogen (BUN): a measurement of urea nitrogen, a waste material that the kidneys help eliminate from the blood via the kidneys.
- Calcium: a critical mineral that enables good bone health, the functioning of muscles, and the cardiovascular and nervous systems. Most calcium is in your bones and teeth, while 1% is in the blood. Blood calcium levels are tightly regulated by hormones and usually remain stable even when dietary intake varies. Abnormally high levels of calcium may be present in certain cancers, kidney failure, lung diseases, or thyroid abnormalities.
- Chloride: an electrolyte that functions along with sodium, potassium, and bicarbonate to enable a wide range of processes in the body, such as nerve and muscle activity, as well as acid-base balance.
- Creatinine: a by-product of normal muscle activity, a waste product normally filtered and removed from the blood by the kidneys. CMP results are commonly interpreted in conjunction with the estimated glomerular filtration rate (eGFR) to assess how well the kidneys filter waste products from the blood, and are a good indicator of overall kidney function.
- Glucose: the main sugar found in blood that is the primary source of energy for the brain and body. This is also known as blood sugar, and elevated levels may indicate diabetes or prediabetes.
- Potassium: an electrolyte present in all tissues of the body and that comes from the foods you eat. It regulates fluid balance and acid-base balance, thereby controlling muscle and nerve function. High potassium levels are seen in kidney disease, whereas high or low potassium levels can affect the heart.
- Sodium: an electrolyte that promotes healthy fluid levels and acid-base balance in the body. It facilitates proper muscle and nerve function. The kidneys help regulate your body’s sodium levels. High levels of sodium may be from high-sodium diets, dehydration, certain drugs, diabetes, or kidney disease, whereas low sodium levels can result from excessive sweating, burns, vomiting, diarrhea, poor nutrition, thyroid, adrenal, kidney, heart, or cirrhosis.
- Total protein: a measurement of the sum of albumin and globulins (made by the liver and the immune system that help fight infections and transport nutrients). High protein levels are seen in chronic infections (HIV, hepatitis) and in bone marrow disorders. Low protein levels are associated with liver or kidney problems, celiac disease, congestive heart failure, or malnutrition. Intense exercise, diet, stress, and pregnancy can also alter protein levels.
When should I get a CMP?
The CMP may be appropriate in a range of different circumstances. For diagnostic purposes, it may be prescribed when you have symptoms connected to your kidneys, liver, or metabolism. It may also be helpful when you have a general symptom, such as fatigue, that can be caused by many different health conditions.
As a monitoring tool, a CMP may be prescribed if you have had a prior abnormal test and the doctor wants to check if your levels remain abnormal.
A CMP can also be used after a treatment has been started to see how your blood levels have changed. For example, if you are starting a new medication that can alter kidney or liver function, the CMP may be a useful tool for making sure these organs are still working properly.
A CMP is often included in routine blood testing during preventive health visits. However, whether it is necessary depends on your health history, risk factors, and doctor’s clinical recommendations.
Finding a CMP Test
How to get tested
The CMP uses a blood sample that is normally taken in a medical laboratory, office, or clinic. The test is done after being prescribed by a doctor, and the analysis is conducted in a laboratory.
Can I take the test at home?
No, this test is almost always conducted by obtaining a sample in a lab or other medical setting.
The full CMP is not available as an at-home test kit, though you can order a CMP online and take your form to a lab for sample collection. But some of the 14 components of the panel, such as the measurements commonly included in a liver panel, may be available with an at-home kit. In these kits, you take a fingerstick blood sample and mail it to a laboratory for analysis. Results are typically available within 1 to 3 business days.
How much does the test cost?
There is no set price for the CMP. Instead, the cost depends on whether you have insurance coverage and where the blood sample is taken and analyzed.
The charges for CMP testing may include the technician’s fee for drawing your blood, the lab’s analysis fees, and any office visits. If your insurance plan won’t cover the test, you can use your FSA or HSA to pay for testing.
For specific details about expected costs, contact your doctor’s office and your insurance provider, and make sure to ask about any copays or deductibles that you may be responsible for paying.
Taking a CMP Test
A blood sample is needed for the CMP. All 14 measurements in the panel are conducted with the same sample, which is taken from a vein in your arm. This blood draw is usually done in a health clinic, doctor’s office, hospital, or laboratory.
Before the test
You may need to fast before your CMP blood draw, especially if accurate glucose measurements are important. In many cases, fasting may not be required. Follow the instructions provided by your health care provider or laboratory.
In preparation for the test, also inform your doctor about any medications or dietary supplements that you regularly take. Your doctor can then tell you whether you need to adjust your medication schedule before taking your blood sample.
During the test
A blood draw is a routine procedure that generally takes less than a few minutes. While you are seated, a technician will tie an elastic band around the upper section of your arm. They will use an antiseptic to clean the part of your arm where your blood will be drawn. A needle will be inserted into your vein, and a vial of blood will be withdrawn.
You may experience some pain, often a brief sting, when the needle is inserted into and removed from your arm.
After the test
After a vial of blood has been drawn, the needle is removed to finish the procedure. The technician will usually apply a swab or bandage to stop bleeding from the puncture site. Some people find that their arm is tender or may have bruising after their blood is drawn, but serious or lasting effects are uncommon.
Since you have to fast before the test, you may want to bring something to eat after your blood is drawn. Most people can return to normal activities immediately after a blood draw.