A bicarbonate blood test measures the level of bicarbonate in your blood, a key component that helps maintain the body’s acid-base balance. Also known as a CO₂ test, it shows how well your lungs and kidneys are working together to keep your pH within a healthy range.

This test is important because imbalances in bicarbonate levels can signal issues with breathing, kidney function, or metabolic health. Tracking these levels provides doctors with valuable insights into conditions such as metabolic acidosis, respiratory problems, or chronic illnesses that affect your body’s balance.

This guide explains what it is, how it works, what your results mean, and how you can book a comprehensive blood test to check your Bicarbonate.

What is Bicarbonate?

Bicarbonate is a type of electrolyte, a substance in your blood that helps keep your body’s acid and base levels balanced. Think of it as a natural “buffer system” that prevents your blood from becoming too acidic or too alkaline, similar to how baking soda can balance acidity when used in cooking.

Your body produces bicarbonate mainly through the kidneys, and it works closely with your lungs. When you breathe out carbon dioxide, it helps regulate the amount of acid in your blood. Together, the lungs and kidneys keep your pH within a narrow, healthy range—essential for your cells, muscles, and organs to function properly.

Quick facts about bicarbonate:

• It is also called HCO₃⁻ in medical terms.
• Normal blood levels usually range from 22 to 29 mmol/L.
• Abnormal levels can point to issues with breathing, kidney health, or metabolism.

In short, bicarbonate plays a crucial role in keeping your body’s internal environment stable. Without the right balance, your body would struggle to perform everyday processes like energy production and waste removal.

Why is Bicarbonate important?

Bicarbonate is a primary blood buffer that keeps your acid–base (pH) balance within a narrow range so cells can make energy, muscles contract, and organs work properly. When bicarbonate is low or high, it signals underlying problems in metabolism, lung function, or kidney health—conditions that, if missed, can shorten healthy lifespan.

In Australia, chronic kidney disease (CKD)—a major cause of low bicarbonate and metabolic acidosis—affects an estimated 11% of adults (about 1.7 million people). That scale makes acid–base monitoring clinically relevant for a large portion of the population.

Globally, metabolic acidosis becomes more common as CKD advances: one large cohort reported metabolic acidosis in 13.2% of all CKD patients, rising to 27.6% at stage 4 and 46.4% at stage 5. These shifts are tracked clinically using serum bicarbonate, underscoring its value for risk assessment and timely treatment.

Knowing—and acting on—your bicarbonate level equips you and your clinician to catch problems early, tailor care, and protect long-term metabolic health.

When should you get a Bicarbonate test?

A bicarbonate blood test is usually ordered by your GP as part of a broader health check, but there are certain scenarios where it’s especially important. You may be advised to get tested if you have:

• Unexplained symptoms such as fatigue, rapid breathing, nausea, or confusion.
• Chronic conditions, including kidney disease, diabetes, or lung disease, that may affect acid–base balance.
• A family history of kidney disorders or metabolic conditions that increase the risk of acidosis or alkalosis.
• Pregnancy, where monitoring electrolytes helps ensure both maternal and foetal health.
• Follow-up after abnormal results from other blood markers, such as creatinine, urea, or anion gap.
• A GP or specialist referral when investigating metabolic acidosis, respiratory issues, or unexplained blood chemistry changes.

Getting tested at the right time helps doctors detect imbalances early, guide treatment, and support long-term health.

How does the Bicarbonate test work in Australia?

In Australia, a bicarbonate test is a standard blood test that measures the amount of bicarbonate (HCO₃⁻) in your blood, usually as part of an electrolyte panel or a larger metabolic profile. A pathology nurse will take a small blood sample from a vein in your arm. No fasting is required unless your doctor has requested other tests at the same time, such as glucose or lipid levels.

When it comes to the Bicarbonate test cost Australia, Medicare generally covers the fee if your GP has ordered the test for clinical reasons—for example, to investigate symptoms like shortness of breath or to monitor conditions such as chronic kidney disease or diabetes. If you decide to have the test privately without a referral, costs can vary but typically fall between AUD $30 and $80 depending on the provider and whether it is bundled in a broader blood test panel.

Australians usually access the bicarbonate test through GP referrals to pathology services like Sullivan Nicolaides Pathology, Douglass Hanly Moir, or Australian Clinical Labs, which bulk bill under Medicare in most cases. Private wellness clinics also offer comprehensive blood test panels that include bicarbonate, giving people the option to monitor their acid–base balance alongside other key biomarkers.

This makes the bicarbonate test widely available, affordable, and easy to arrange across Australia.

What do my Bicarbonate test results mean?

Bicarbonate results show how well your body is keeping its acid–base balance in check. Normal levels mean your kidneys and lungs are working together properly, while results outside the healthy range can point to an underlying issue with breathing, metabolism, or kidney function.

Here’s a simple guide to help understand your results:

It’s important to remember that results should always be reviewed by your doctor, who will interpret them in the context of other blood markers and your overall health. A single abnormal result doesn’t confirm a diagnosis but signals that further investigation may be needed.

Bicarbonate in context (other relevant tests)

A bicarbonate result gives valuable insight into your body’s acid–base balance, but it is most useful when reviewed with other blood markers. This is because pH regulation depends on how your kidneys and lungs interact with electrolytes and metabolic processes.

Doctors often interpret bicarbonate levels together with:

• Anion gap helps identify if acidosis is due to kidney problems, diabetes, or other metabolic causes
• Creatinine and urea measure kidney function and show whether low bicarbonate is linked to reduced filtration
• Chloride and potassium are electrolytes that influence acid–base balance and are usually tested in the same panel
• Glucose is important for identifying diabetic ketoacidosis, a condition that can lower bicarbonate

By looking at bicarbonate alongside these related markers, healthcare providers can build a clearer picture of what is happening in your body and decide on the right next steps. This combined view helps detect whether imbalances are temporary or signs of a more serious condition that requires treatment.

Lifestyle and practical steps

Bicarbonate levels reflect how well your body maintains its acid–base balance, and everyday habits can support this process. While treatment for underlying conditions is essential, simple lifestyle adjustments may help your body stay in balance.

1. Eat a balanced diet: Focus on plenty of fruits and vegetables, which provide alkaline-forming minerals. Limit highly processed foods, sugary drinks, and excess animal protein, which can increase acid load. Staying hydrated also supports kidney function and electrolyte balance.
2. Stay active: Moderate exercise such as walking, swimming, or cycling helps your lungs and circulation regulate bicarbonate. Avoid over-exercising without recovery, as this can increase acid build-up.
3. Prioritise sleep: Aim for 7–9 hours of restful sleep each night. Good sleep supports breathing patterns, metabolism, and hormone balance, all of which help maintain healthy bicarbonate levels.
4. Manage stress: Stress affects metabolism and breathing, which can influence acid–base balance. Practices like mindfulness, meditation, and yoga can help reduce this impact.
5. Keep hydration steady: Drinking enough water throughout the day assists your kidneys in clearing excess acids and maintaining balance.

These supportive steps encourage your body to keep bicarbonate levels stable. The best starting point is testing. Once you know your levels, you can take personalised steps.

FAQs about the Bicarbonate Test in Australia

What is a bicarbonate blood test used for?

A bicarbonate test measures the amount of bicarbonate in your blood, which helps regulate acid–base balance. It is used to check for conditions affecting your lungs, kidneys, or metabolism.

How much does a bicarbonate test cost in Australia?

If ordered by your GP for medical reasons, the test is usually covered by Medicare. Private testing can cost between AUD $30 and $80, depending on the provider and whether it is part of a larger blood panel.

Do I need a GP referral for a bicarbonate test?

In most cases, yes. Your GP will request the test if you have symptoms or a condition that needs further investigation. Some private pathology services offer direct access as part of wellness panels.

Is the bicarbonate test safe during pregnancy?

Yes, the test is safe in pregnancy. It can be useful for monitoring electrolytes and acid–base balance, especially if there are concerns about maternal or fetal health.

What symptoms might prompt a bicarbonate test?

Symptoms such as fatigue, rapid breathing, nausea, confusion, or unexplained weakness may prompt your doctor to request a bicarbonate test.

What is the normal range for bicarbonate?

The typical reference range is 22–32 mmol/L. Levels outside this range may suggest metabolic or respiratory imbalance, which your doctor will interpret alongside other test results.

Can I eat before a bicarbonate test?

Yes, no fasting is required for a bicarbonate test unless your doctor has ordered additional tests that need fasting, such as blood glucose or lipid levels.

Conclusion

Bicarbonate is a vital part of your body’s natural buffering system, helping to maintain a stable acid–base balance so that your cells, muscles, and organs can function properly. When bicarbonate levels are too low or too high, it may point to underlying issues with your kidneys, lungs, or metabolism that need attention. Testing gives doctors clear insights into these processes and helps guide further care.

Knowing your bicarbonate levels is more than just a number—it’s an opportunity to understand how your body is managing balance and resilience. With this information, you and your healthcare provider can make informed choices to protect long-term health and wellbeing.

Take control of your health today. Sign up for our comprehensive blood test and get clear insights into your bicarbonate and more than 50 other key markers.

References

• Healthdirect Australia. “Full blood count (FBC).
• Better Health Victoria (Victoria Department of Health). “Blood count.”‍
• MyDr Australia. “Full blood count (FBC)” test page.