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Blood Chemistry Tests-What is a Chem 7?

What Do Your Lab Test Results Mean?

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Updated April 09, 2014

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Blood Tests

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Blood Chemistry Tests and Results

Blood chemistry tests are often ordered prior to surgery or a procedure to examine the general health of a patient. This blood test, commonly referred to as a Chem 7 because it looks at 7 different substances found in the blood, is routinely performed after surgery as well.

The blood is drawn from a vein, or if a special IV is present, it can be drawn from the IV without a “stick”. Your doctor may have this blood test done several days prior to the procedure or it may be drawn immediately prior to your surgery.

Please keep in mind that there are many reasons that the results this test may be higher or lower than normal. It is important to consult with your physician regarding the results, as there are many factors that can contribute to results that do not fall within the normal range.

This test is known by multiple names including a SMAC7, Sequential Multi-Channel Analysis with Computer 7, Metabolic Panel, Basic Metabolic Panel and Metabolic 7, but most medical professionals refer to it as a chem 7. The results of the chem 7 are different depending on the country where the test is done. The first set of results listed is for the United States which vary slightly between labs. The additional results listed are for metric based countries, designated international.

Blood Chemistry Components

  • Blood Urea Nitrogen (BUN)

    BUN is a measure of kidney function. A high level may indicate that the kidneys are functioning less than normal.

    Normal Values: 8-25mg/100ml (USA)2.9-8.9 mmol/L (International)

  • Carbon Dioxide (CO2)

    This test measures the amount of carbon dioxide in the blood. Most carbon dioxide is present in the form of bicarbonate, which is regulated by the lungs and kidneys. The test result is an indication of how well the kidneys, and sometimes the lungs, are managing the bicarbonate level in the blood.

    Normal Values: 24-30 mEq/L (USA) 24-30 mmol/L (International)

  • Creatinine

    Creatinine is produced by the body during the process of normal muscle breakdown. High levels may indicate kidney impairment, low blood pressure, high blood pressure or another condition. Some medications can also cause a higher than normal level of blood creatinine. Low levels may be caused by late stage muscular dystrophy, myasthenia gravis and over hydration.

    Normal Values:

    Men: 0.2-0.5 mg/dl (USA) 15-40 umol/L (International)

    Women: 0.3-0.9mg/dl (USA) 25-70 umol/L (International)

  • Glucose

    This test shows the level of glucose in the blood. High levels of glucose can indicate the presence of diabetes or another endocrine disorder. Keep in mind that some medications and the timing of the test in relation to meals can radically alter the results. Do not assume that your results indicate a problem until you have consulted with your physician.

    Normal Values: 70-110 mg/ml (USA) 3.9-5.6 mmol/L (International)

  • Serum Chloride (Cl)

    This test shows the level of chloride in the blood. Chloride binds with electrolytes including potassium and sodium in the blood and plays a role in maintaining the proper pH of the blood. Chloride levels can vary widely if the patient is dehydrated or overly hydrated, if the kidneys are not functioning properly. Heart failure and endocrine problems can also contribute to abnormal chloride results.

    Normal Values: 100-106 mEq/L (USA) 100-106 mmol/L (International)

  • Serum Potassium (K)

    This test shows the level of potassium in the blood. Potassium plays an important role in muscle contractions and cell function. Both high and low levels of potassium can cause problems with the rhythm of the heart so it is important to monitor the level of potassium after surgery. Patients who are taking diuretics regularly may require regular blood tests to monitor potassium levels, as some diuretics cause the kidneys to excrete too much potassium.

    Normal Values: 3.5-5 mEq/L (USA) 3.5-5 mmol/L (International)

  • Serum Sodium (Na)

    This portion of the test shows the amount of sodium present in the blood. The kidneys work to excrete any excess sodium that is ingested in food and beverages. Sodium levels fluctuate with dehydration or over-hydration, the food and beverages consumed, diarrhea, endocrine disorders, water retention (various causes), trauma and bleeding.

    Normal Values: 135-145 mEq/L (USA) 3.5-5 mmol/L

More Common Tests Before & After Surgery

Sources:

Chem7. Medline Plus. National Institutes of Health http://www.nlm.nih.gov/medlineplus/ency/article/003462.htm

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