Chem 7 Panel: Blood Chemistry Test

A chem 7 blood panel is a blood chemistry test that is part of a series of tests ordered before surgery. The tests help the medical team understand the patient's general health status.

Also known as chem 7 or chem 7 basic metabolic panel, it looks at seven different substances in the blood. A chem 7 is also routinely performed after surgery. This helps make sure the person is well in the days following the operation.

This article discusses the chem 7 blood chemistry test, what is being tested, and what the results mean.

Purpose of a Chem 7 Test

The chem 7 blood test is known by a few different names, including:

• Sequential multi-channel analysis
• Computer 7 (SMAC7)
• Metabolic 7
• Basic metabolic panel (BMP)

Most medical professionals call it a chem 7 or BMP. A comprehensive metabolic panel (CMP) is similar but includes seven additional tests, for a total of 14.

The seven tests included in the chem 7 panel include:

• Blood urea nitrogen (BUN)
• Carbon dioxide
• Creatinine
• Glucose
• Serum chloride
• Serum potassium
• Serum sodium

What to Expect From a Chem 7 Test

Your healthcare provider may order the chem 7 test before a procedure or as a routine test when having a physical exam.

Fasting at least eight hours before drawing bloodwork for the basic metabolic panel is often recommended but not always practical. For example, if the test is taken at the doctor's office or hospital without prior planning, fasting before the test may not be possible.

Blood will be drawn from a vein or an intravenous (IV) line. The lab can usually return results very quickly.

The lab report will provide reference ranges for each of the seven substances. A result is normal if it falls between the high and low values in the range. Anything below or above the reference range is considered abnormal. There is some flexibility in the way the results are interpreted, based on:

• Your age
• Your general health, including any chronic medical conditions
• Differences in the way results are interpreted from location to location
  

"Deranged" values are excessively high or low. If this is your result, you may need medical intervention before surgery. It's possible you may also be unable to undergo surgery at all.

Your results may look different depending on where you are located in the world.

Blood Urea Nitrogen (BUN)

The waste product urea is made when protein is broken down by the kidneys. Blood urea nitrogen (BUN) measures the amount of nitrogen in your blood that comes from urea. It is a measure of kidney function. A high level may indicate that the kidneys are not functioning normally.

People with early kidney disease may not have any symptoms. A BUN test can help uncover kidney problems at an early stage when treatment can be more effective.

The normal BUN values in adults fall in this range:

• 8 to 23 mg/dL (U.S.)
• 2.9 to 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. Bicarbonate is regulated by the lungs and kidneys. The test can help diagnose or monitor conditions such as high blood pressure and diseases of the kidneys, lungs, or liver.

The normal CO2 values for adults are between:

• 22 and 28 mEq/L (U.S)
• 22 and 29 mmol/L (international)

Creatinine

Creatinine is a waste product. It is produced by the body during normal muscle breakdown. High levels may indicate several conditions, including:

• Blocked urinary tract
• Kidney problems, such as kidney damage or failure, infection, or reduced blood flow
• Dehydration
• Muscle problems, such as breakdown of muscle fibers (rhabdomyolysis)
• Problems during pregnancy, such as seizures caused by eclampsia or high blood pressure caused by preeclampsia

Other conditions may also cause high creatinine.

Some medications can also cause a higher-than-normal level of blood creatinine. Low levels may be caused by conditions such as:

• Late-stage muscular dystrophy
• Myasthenia gravis
• Overhydration
• Malnutrition

The normal creatinine values for adults fall in this range:

• 0.6 to 1.2 mg/dL (U.S.)
• 7.0 to 17.6 umol/L (international)

Glucose

The blood glucose test is a measure of your blood sugar. Blood sugar is also called glucose. High glucose levels may indicate diabetes or another endocrine disorder. Your endocrine system helps regulate many of your body functions.

Blood glucose levels should be measured while fasting for at least eight hours. It is used to screen for diabetes and should be below 100 mg/dL. However, levels can rise after eating and be as high as 140 mg/dL in people without diabetes.

Various factors can influence blood glucose test results, including:

• Some medications
• The timing of the test in relation to meals

These are the normal glucose values for adults:

• 70 to 99 mg/mL (U.S.)
• 3.9 to 6.1 mmol/L (international)

Serum Chloride

The serum chloride (Cl) test measures the level of chloride in your blood. Chloride binds with electrolytes such as potassium and sodium. It helps maintain the proper pH balance of the blood. Chloride levels can vary widely if you are dehydrated or overhydrated.

Chloride is often measured with other electrolytes to diagnose or monitor conditions, such as kidney disease, heart failure, liver disease, and high blood pressure.

Normal serum chloride values in adults are as follows:

• 96 to 106 mEq/L (U.S.)
• 96 to 106 mmol/L (international)

Serum Potassium

The serum potassium (K) test shows the level of potassium in the blood. Potassium plays a role in muscle contractions, nerve activity, and cell function. Your cells, nerves, heart, and muscles need potassium to work properly.

Both high and low levels of potassium can cause problems with heart rhythm. This is why it is important to monitor potassium levels before and after surgery.

High potassium levels (hyperkalemia) may be a sign of:

• Kidney disease
• Addison disease (a disorder of the adrenal glands)
• Injuries, burns, or surgery causing cells to release extra potassium into your blood
• Type 1 diabetes that is not well controlled
• The side effects of certain medicines, such as diuretics ("water pills") or antibiotics
• A diet too high in potassium (not common) 

Low potassium in the blood (hypokalemia) may be a sign of:

• Taking diuretics
• Fluid loss from diarrhea, vomiting, or heavy sweating
• Using too many laxatives
• Adrenal gland disorders, including Cushing's syndrome and aldosteronism
• Kidney disease
• Alcohol use disorder (AUD)
• A diet too low in potassium (not common)
  

Serum Sodium

The serum sodium (Na) test measures the amount of sodium in the blood. Like other electrolytes, sodium helps your nerves and muscles work properly.

Normally, excess sodium in the things you eat and drink is excreted by the kidneys. Sodium blood test results that are higher than normal may be a sign of:

• Dehydration
• Diuretic medications (water pills)
• A disorder of the adrenal glands
• Kidney disease
• Diabetes insipidus (uncommon)

Sodium blood test results that are lower than normal may be a sign of:

• A loss of sodium from diarrhea or vomiting
• Kidney diseases
• Cirrhosis of the liver
• Heart failure
• Certain brain and lung diseases
• Certain types of cancer
• Medications such as over-the-counter pain relievers and some antidepressants
• Addison disease
• Malnutrition

These are the normal serum sodium value ranges for adults:

• 136 to 142 mEq/L (U.S.)
• 135 to 145 mmol/L (international)

Summary

A chem 7 is a test that looks at seven different substances in the blood. It is often ordered before surgery and during routine physical exams. The results are an indication of your general health status.

The test measures your levels of blood urea nitrogen (BUN), carbon dioxide, creatinine, glucose, chloride, potassium, and sodium.

The blood is sent to a lab and the lab report shows your levels of each substance. Levels that are too high or too low can indicate a health problem. Abnormal results may be a reason to cancel or postpone surgery.