Bicarbonate concentration in serum or plasma

Bicarbonate is a form of carbon dioxide (CO2) in your blood that helps keep your body's acid-base balance within a healthy range, playing an important role in how your cells, kidneys, and lungs function every day.

Bicarbonate (HCO₃⁻) is a critical buffer in your blood that helps maintain acid-base balance. It works alongside carbon dioxide and oxygen to keep your blood pH stable, which is essential for many bodily functions, including muscle and nerve function. When levels are too high or too low, it can signal underlying health issues, such as metabolic disorders or kidney problems.

Your doctor may order this test if you have symptoms of an acid-base imbalance, such as fatigue, vomiting, diarrhea, or difficulty breathing, or to help monitor kidney, lung, or metabolic conditions over time.

Doctors may order a bicarbonate test to check for conditions like metabolic acidosis (too much acid in the blood) or alkalosis (too much base), especially if you have symptoms like confusion, rapid breathing, or irregular heartbeat. It’s also used in monitoring kidney function, diabetes, or after treatments for conditions like heart failure or severe dehydration.

Usually no special preparation is needed, but you should follow any instructions from your healthcare provider, including whether to fast beforehand or temporarily avoid certain medications, supplements, or fluids before your blood is drawn.

No special preparation is usually needed, but you may be asked to fast for a few hours before the draw if your doctor specifies it. Bring any medications or supplements you’re taking, as they could affect results. Avoid smoking or caffeine for at least 30 minutes before the test if instructed.

A healthcare professional will clean the skin on your arm, wrap an elastic band around your upper arm, and draw a small blood sample from a vein, which typically takes only a few minutes and causes little more than brief discomfort.

A healthcare provider will draw blood from a vein in your arm using a small needle. You may feel a slight pinch, but it’s usually over quickly. The blood sample is then sent to a lab for analysis. The test typically takes a few minutes, and you can resume normal activities afterward.