Receiving your blood test results can raise questions. The line “bicarbonates” or “HCO3-” often attracts attention. Understanding this parameter is essential, as it offers insight into the body’s internal balance. This article aims to clarify what this marker is, what its variations mean, and in which situations medical advice is relevant. It is a guide to transform technical data into understandable information about your health.

What are Bicarbonates in Blood?

Definition and Fundamental Role

Blood bicarbonates, also called hydrogen carbonate ions (HCO3-), are essential electrolytes. They play a central role in maintaining the body’s acid-base balance. In other words, they ensure that the pH of your blood stays within a very precise range, which is vital for cells to function properly.

The body produces these molecules mainly through the kidneys. These organs filter the blood and constantly adjust the amount of bicarbonates to meet the body’s needs. The liver also participates in their metabolism.

The Body’s Buffer System

Bicarbonates act as the blood’s main buffer system. They can be compared to a stabilizer that neutralizes excess acid or base. For example, if the blood becomes too acidic, bicarbonates capture the ions responsible for this acidity. Conversely, if the blood becomes too basic (alkaline), they release them to restore balance.

This regulation is indispensable. Most chemical reactions and enzymes in our body function correctly only under stable pH conditions. Without this system, vital functions would be compromised.

Normal Values and Interpretation

Laboratories measure bicarbonate concentration during a blood test. The result indicates the body’s ability to manage its acid-base balance. It helps evaluate kidney function and general metabolic status.

The normal value for blood bicarbonate is generally between 22 and 29 millimoles per liter (mmol/L) in an adult. However, this range may vary slightly from one laboratory to another. Your test report will always indicate the specific reference values.

• A level below 22 mmol/L may indicate metabolic acidosis.
• A level above 29 mmol/L may suggest metabolic alkalosis.

Why is Understanding This Parameter Important?

Bicarbonates do not function alone. They are part of a complex system that includes other electrolytes like sodium, potassium, and chloride. Together, they maintain the body’s internal balance, a state called homeostasis.

An undetected imbalance can have long-term consequences. For example, even mild chronic acidosis can force the body to draw calcium from bones to neutralize excess acid. This can weaken the skeleton over time. Furthermore, studies suggest that a low and persistent bicarbonate level may be associated with faster progression of certain kidney diseases.

This marker also has a direct impact on energy, muscle function, and respiration. It is therefore a key element that doctors evaluate to make diagnoses and guide therapeutic decisions.

How to Read and Understand Your Bicarbonate Analysis?

Decoding Blood Results

On your results sheet, bicarbonates are usually found in the “Electrolytes” or “Ionogram” section. They may appear under the names “HCO3-“, “Bicarbonates”, or “Alkaline Reserve”. The value is given in mmol/L. If your result is outside the reference range, it is often indicated by an asterisk or a different color.

It is important to note that 5% of healthy people may have values slightly outside the norms without it being pathological. This is why interpretation should always be done in a global context.

Checklist for a First Analysis

To better understand your result, you can follow these steps:

1. Compare: Is your value within the normal range, low, or high?
2. Correlate: Are other electrolytes (sodium, potassium, chloride) also abnormal?
3. Track: How does this result compare to your previous analyses?
4. Contextualize: Do you have symptoms? Are you taking medication? How is your hydration?

Which Pathologies are Linked to Bicarbonate Imbalance?

An abnormal bicarbonate level is a sign, not a disease in itself. It guides the doctor towards an underlying cause.

Consequences of Low Bicarbonate Levels (Metabolic Acidosis)

Metabolic acidosis occurs when the body produces too much acid or when the kidneys do not eliminate enough.

• Diabetic Ketoacidosis: Occurs in case of poorly controlled diabetes. The body produces acids called ketone bodies.
• Kidney Failure: Failing kidneys can no longer eliminate acids resulting from normal metabolism.
• Severe Diarrhea: Causes a significant loss of bicarbonates in stools.
• Intoxication: Ingesting substances like high-dose aspirin can cause acidosis.

Symptoms may include severe fatigue, rapid and deep breathing, or confusion.

Consequences of High Bicarbonate Levels (Metabolic Alkalosis)

Metabolic alkalosis is often due to excessive loss of acids or excess bases.

• Prolonged Vomiting: The loss of hydrochloric acid from the stomach causes an increase in bicarbonates.
• Taking Certain Medications: Some diuretics or excessive consumption of antacids containing bicarbonate can be the cause.
• Hormonal Conditions: More rarely, diseases like hyperaldosteronism or Cushing’s syndrome can lead to alkalosis.

Symptoms may include muscle cramps, tingling, or tremors.

Practical Tips and Follow-up

When to See a Doctor?

Medical advice is necessary in the following situations:

• The level is significantly outside the norms (e.g., below 18 or above 32 mmol/L).
• The variation is rapid and significant between two analyses.
• The abnormal result is accompanied by symptoms (fatigue, confusion, respiratory problems).
• Other electrolytes are also disturbed.

In case of severe symptoms, an emergency room consultation may be required. For a slight deviation without symptoms, your doctor may simply recommend a check after a few weeks or months.

Role of Diet

In case of mild chronic metabolic acidosis, and always in agreement with your doctor, certain adjustments may be helpful. A diet rich in fruits and vegetables can help reduce the acid load. Conversely, an excess of animal protein can increase it.

In case of alkalosis, it is important to avoid overconsumption of alkalinizing substances, such as certain antacids.

Frequently Asked Questions about Bicarbonate

Can Medications Affect This Parameter?

Yes. Some diuretics can increase bicarbonate levels (alkalosis). Conversely, medications like topiramate (an antiepileptic) or acetazolamide can decrease it (acidosis). It is therefore crucial to inform your doctor about all treatments you are undergoing.

How Does Altitude Affect Bicarbonates?

At high altitudes, oxygen scarcity leads to faster breathing. This hyperventilation eliminates more CO2, making the blood more alkaline. To compensate, the kidneys excrete more bicarbonates, lowering their level in the blood. This is a normal adaptation.

Why Does the Level Vary Between Two Blood Draws?

Slight variations (±2 mmol/L) are common and rarely significant. They can be due to hydration, a recent meal, intense physical effort, or even stress related to the blood draw.

What is the Link with Cardiovascular Risk?

Recent research suggests that even mild chronic metabolic acidosis could be a risk factor for kidney and cardiovascular health. This highlights the importance of regular monitoring in people at risk.

How Can Eating Disorders Influence the Level?

Repeated vomiting (bulimia) causes acid loss and thus metabolic alkalosis (high levels). Conversely, severe malnutrition (anorexia) can lead to acidosis. These imbalances are dangerous and require strict medical supervision.

Additional Resources

To deepen your knowledge of this blood marker, here is a reliable resource:

• Medline Plus

Don’t wait any longer to take control of understanding your blood tests. Understand your laboratory analysis results in minutes with our aidiagme.com platform; your health deserves this special attention!

Decipher Other Markers

• More biomarkers articles are available here.