Blood Test

What it is: A bicarbonate (carbon dioxide) test measures the level of bicarbonate in the blood, an electrolyte that helps maintain the body's acid-base balance.

Why it's ordered: Usually ordered as part of an electrolyte panel, basic metabolic panel, or comprehensive metabolic panel to evaluate acid-base balance, kidney function, or unexplained symptoms like vomiting, breathing difficulty, or fatigue.

What it detects: Bicarbonate helps buffer acids and moves carbon dioxide through the bloodstream. Abnormal levels can point to kidney disease, breathing disorders, severe vomiting or diarrhea, or metabolic acid-base imbalances.

Collection & prep: A standard blood draw from a vein in the arm, typically alongside sodium, potassium, and chloride. No special prep is usually required unless it's part of a fasting panel.

Results:

• High – may reflect metabolic alkalosis or a compensatory response to a breathing disorder
• Low – may reflect metabolic acidosis, kidney disease, or fluid loss from vomiting/diarrhea
• Normal – acid-base balance appears stable

Possible complications of an imbalance: Significant bicarbonate abnormalities can affect the heart, muscles, and nervous system, so single abnormal results are usually followed up with repeat testing or blood gas analysis alongside the person's symptoms.