An anion gap blood test is a way to check the levels of acid in your blood. The test is based on the results of another blood test called an electrolyte panel. Electrolytes are electrically charged mineralsthat help control the balance of chemicals in your body called acids and bases. Some of these minerals have a positive electric charge. Others have a negative electric charge. The anion gap is a measurement of the difference-or gap-between the negatively charged and positively charged electrolytes. If the anion gap is either too high or too low, it may be a sign of a disorder in your lungs, kidneys, or other organ systems.

Other names: Serum anion gap

Your health care provider may have ordered an anion gap blood test if you have signs of an imbalance in your blood acid levels. These signs may include:

• Shortness of breath
• Vomiting
• Abnormal heartbeat
• Confusion

If your results show a high anion gap, you may have acidosis, which means higher than normal levels of acid in the blood. Acidosis may be a sign of dehydration, diarrhea, or too much exercise. It may also indicate a more serious condition such as kidney disease or diabetes.

If your results show a low anion gap, it may mean you have a low level of albumin, a protein in the blood. Low albumin may indicate kidney problems, heart disease, or some types of cancer. Since low anion gap results are uncommon, retesting is often done to ensure the results are accurate. Talk to your health care provider to learn what your results mean.

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