A blood test showing low CO2 primarily indicates low bicarbonate levels, a substance crucial for maintaining the body’s chemical balance. This measurement is part of a routine metabolic panel, providing a snapshot of your body’s chemical and fluid status. It helps healthcare providers assess how well your body regulates its internal environment.
The Role of Bicarbonate
Bicarbonate (HCO3-) plays a fundamental role in the body’s acid-base buffering system. It acts like a natural antacid, helping to neutralize excess acids and bases to keep blood pH within a narrow, healthy range (typically 7.35-7.45). This balance is maintained through a reversible reaction involving carbon dioxide (CO2), water, carbonic acid, and bicarbonate ions.
This buffering action is essential for bodily functions, as even slight shifts in pH can affect how enzymes work and metabolic processes. The lungs and kidneys work together to regulate bicarbonate levels and remove excess acid, ensuring the blood’s pH remains stable. This system effectively manages acids produced daily from normal bodily processes.
What Low Bicarbonate Indicates
A low CO2 reading, meaning low bicarbonate levels, signals metabolic acidosis. This condition occurs when there is too much acid in the body fluids, or when the body loses too much bicarbonate. This imbalance can happen if the kidneys are not removing enough acid or if the body is producing excessive amounts of acid.
The body must maintain a specific pH balance for cells and organs to function correctly. When blood becomes too acidic, it can impair cellular function and, if severe, lead to serious health problems. While mild cases may not show immediate symptoms, worsening acidosis can lead to fatigue, confusion, and a rapid heartbeat.
Common Causes of Low Bicarbonate
Several medical conditions can lead to low bicarbonate levels and metabolic acidosis. One common cause is kidney disease, particularly in its advanced stages, because impaired kidneys struggle to remove sufficient acid from the blood.
Diabetic ketoacidosis (DKA) is another frequent cause, occurring when uncontrolled diabetes leads to the body producing excessive amounts of ketones, which are acidic. Severe diarrhea can also result in low bicarbonate because the body loses bicarbonate-rich fluids from the digestive tract.
Certain medications, such as carbonic anhydrase inhibitors (used to treat glaucoma), can interfere with the body’s ability to maintain bicarbonate levels. Lactic acidosis, an excessive buildup of lactic acid, can also cause low bicarbonate. This can result from factors including prolonged lack of oxygen to tissues, severe infections, or intense physical exertion.
Next Steps After a Low CO2 Result
If a blood test reveals a low CO2 level, consult a healthcare professional. A doctor can properly interpret the result within the context of your overall health and other blood tests. A single low reading might not always be clinically significant, as bicarbonate levels can fluctuate due to various factors like diet and hydration.
Healthcare providers often consider other blood test results, such as electrolytes and kidney function, to gain a complete picture. To diagnose the underlying cause, additional tests may be ordered, including blood work or urine tests. Treatment for low bicarbonate focuses on addressing the root cause of metabolic acidosis. Depending on the cause, treatment might involve managing conditions like diabetes or kidney disease, or oral bicarbonate supplementation.