CBC vs CMP: How These Blood Tests Differ?

Mar 13, 2025 | 1 min read

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CBC and CMP - two common blood tests that often get mixed up. They sound alike, but they check for very different things. One looks at blood cells, the other at organ function and metabolism.

Your doctor can order one or both of these tests to check different aspects of your health

Here’s a simple breakdown of what each test does and when you might need them.

What Are CBC and CMP?

A Complete Blood Count (CBC) is one of the most common blood tests. It checks the health of your blood cells and helps doctors find infections, anemia, or blood disorders. 

Your doctor might order this test to monitor your overall health or look for signs of a medical condition.

A Comprehensive Metabolic Panel (CMP) takes a broader look at your health, checking organ function, blood sugar, and electrolyte balance. It helps doctors detect liver and kidney issues, monitor chronic conditions like diabetes, and assess overall metabolic health.

What Components Do They Measure?

A CBC mainly evaluates the number and quality of your blood cells.s. A CMP, on the other hand, measures your metabolic health and organ function.

CBC Components CMP Components
Red Blood Cells (RBC) Glucose (blood sugar)
White Blood Cells (WBC) Electrolytes (Sodium, Potassium, Chloride, CO2)
Hemoglobin (Hb) Kidney tests (Creatinine,
Blood Urea Nitrogen [BUN])
Hematocrit (Hct) Liver tests (ALT, AST, ALP, Bilirubin)
Platelets Proteins (Albumin, Total Protein)
Mean Corpuscular Volume (MCV) Calcium
Mean Corpuscular Hemoglobin (MCH) -
Mean Corpuscular Hemoglobin
Concentration (MCHC)
-
Red Cell Distribution Width (RDW) -
Mean Platelet Volume (MPV) -

CBC often includes a WBC Differential. This shows the levels of different white blood cells, including neutrophils, lymphocytes, monocytes, eosinophils, and basophils. Doctors use this information to identify infections, allergies, or immune-related conditions more precisely.

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Key Differences Between CBC and CMP

A CBC checks your blood cells. Doctors usually order it if you feel tired, have frequent infections, pale skin, or unexplained bruises.

A CMP checks your overall metabolic health, including organ function and electrolytes. It’s typically ordered if you have ongoing fatigue, nausea, changes in urination, or swelling. It also helps to monitor conditions like diabetes or check blood sugar levels.

You usually don't need any special preparation for a CBC.

Before a CMP test, your doctor might ask you to avoid eating, drinking alcohol, or taking certain medications for accurate results.

Feature CBC CMP
Measures Blood cells Metabolic health
Checks for Anemia, infection, clotting issues Organ function, electrolyte balance
Ordered When Fatigue, infection,
bleeding issues suspected
Liver/kidney disease,
diabetes monitoring
Symptoms That May
Require This Test
Pale skin, frequent infections,
unexplained bruising
Jaundice, swelling,
unusual thirst, frequent urination
Test Preparation No special preparation needed May require fasting; avoid alcohol;
check medication use with doctor

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Please Note!This tool is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always consult a professional before taking any actions.

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