Calculated Bicarbonate (HCO3-)

This test reports the bicarbonate level in your blood using a calculation based on other measured values from your sample. Bicarbonate is a base that buffers acids and is a central part of the body's acid-base regulation.

The result reflects the combined actions of your lungs, which control carbon dioxide, and your kidneys, which reabsorb and generate bicarbonate. It is typically reviewed together with electrolytes and, when available, blood gas results to understand your overall metabolic status.

Bicarbonate helps your body keep a steady internal environment. Clinicians use this test to evaluate acid-base disorders, monitor kidney and lung conditions, and follow illnesses that can shift your body's acidity, such as diabetes, severe infections, and dehydration.

Your clinician may order it when you have symptoms like rapid breathing, nausea, vomiting, or confusion, or when you are receiving treatments that can affect acid-base balance, including diuretics or bicarbonate therapy. It is commonly included in electrolyte panels and blood gas assessments.

Lower results often suggest a tendency toward acidity from conditions such as metabolic acidosis, diarrhea-related bicarbonate loss, kidney problems, or compensation for high carbon dioxide. Higher results can indicate metabolic alkalosis, volume depletion, vomiting, or compensation for low carbon dioxide. Because this value is calculated, different analyzers and methods can yield slightly different numbers.

Your result should be interpreted with your symptoms, medications, other electrolytes, the anion gap, and, if done, blood gas measurements. If the finding is unexpected or does not fit your clinical picture, your care team may repeat the test, check a direct total carbon dioxide, or perform additional testing to find the cause and guide treatment.