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Chem 7 Blood Test Components

written by: Leigh A. Zaykoski•edited by: Leigh A. Zaykoski•updated: 2/28/2010

The chem 7 blood test checks the levels of seven substances in the blood. This test helps doctors identify problems with the kidneys and other organs, allowing them to develop appropriate treatment plans.

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    Chem 7 Components

    The chem 7 blood test checks the levels of creatinine, blood urea nitrogen (BUN), carbon dioxide, chloride, glucose, sodium and potassium in the blood. This allows doctors to identify diseases and disorders of the kidneys and screen for diabetes and other blood sugar disorders. Performed on a small sample of blood taken from the arm, this test causes little discomfort and has few risks.

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    BUN & Creatinine

    BUN and creatinine, waste products created during the metabolism of protein, leave the body in the urine. The kidneys filter these waste products prior to urine production and then eliminate them during urination. When kidney function declines, the kidneys do not filter these waste products properly, allowing their blood concentrations to increase. High levels of these substances cause itchy skin, nausea, vomiting, and fatigue. As kidney function continues to decline, hemodialysis becomes necessary. During hemodialysis, a machine filters BUN, creatinine, and other substances out of the blood and returns the filtered blood to the circulatory system.

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    Glucose, also referred to as blood sugar, provides energy for the human body. Normal levels of glucose in the blood range from 70 to 110 mg/ml, or 3.9 to 5.6 mmol/L (international measurement). Abnormal blood glucose levels help doctors identify diabetes and other endocrine disorders. Since medications and the timing of your meals affect blood glucose levels, your doctor will instruct you on how to prepare for this test so you get the best results.

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    Potassium & Sodium

    The chem 7 blood test checks the levels of several electrolytes in the blood. These electrolytes include sodium and potassium. Both electrolytes are necessary for normal function of the human body. Sodium helps regulate the amount of water in the body and assists with the transmission of nerve signals in the brain, muscles, and nervous system. Potassium controls nerve impulse transmission and muscle contraction, making it especially important for normal respiration and heartbeat. Abnormal levels of these electrolytes indicate several conditions. Temporary alterations in sodium and potassium levels indicate dehydration or trauma to the body. Chronic abnormalities often indicate kidney disorders, such as chronic kidney disease or polycystic kidney disease.

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    Chloride & Carbon Dioxide

    Chloride binds with sodium and potassium and helps maintain the acid-base balance of the blood. Levels of this substance fluctuate in kidney disease, heart failure, endocrine abnormalities, and dehydration. Carbon dioxide appears in the blood as bicarbonate. The kidneys and lungs regulate the amount of carbon dioxide in the blood, so abnormal levels of this substance may indicate problems with either set of organs.

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    Complementary Testing

    The chem 7 blood test gives doctors an idea of how well certain organs function. Doctors may order other blood tests to determine if other problems exist. The comprehensive metabolic panel, which includes the same components as the chem 7 panel, also includes tests for calcium, total protein, albumin, ALT, AST, ALP, and bilirubin.