Bicarbonates (CO2)
This test measures the level of bicarbonate in your blood, which helps maintain the body's acid-base balance. It is commonly part of an electrolyte or metabolic panel and requires a simple blood draw.
12 hours
Turnaround
Blood
Sample
What the Bicarbonates (CO2) test tells you
Bicarbonate is the body's main chemical buffer, and this test measures how much of it your blood is carrying. It is often reported as "CO2" on a results sheet, which causes understandable confusion — the label refers to total carbon dioxide content, and almost all of that is present as bicarbonate rather than as the gas you breathe out. It is a standard component of electrolyte and metabolic panels and is measured from the same blood sample as sodium, potassium and chloride.
Your body works within a narrow band of acidity, and bicarbonate is the buffer that defends it. Acid is produced continuously by ordinary metabolism, and bicarbonate neutralises it. Two organs then keep the system balanced: the lungs adjust how much carbon dioxide is exhaled, and the kidneys adjust how much bicarbonate is retained or discarded. Because these two systems compensate for one another, the bicarbonate value is read as part of a picture rather than as a standalone figure — it tells your doctor which direction the balance has shifted and often hints at whether the cause is metabolic or respiratory.
A fall in bicarbonate generally means acid is accumulating or bicarbonate is being lost. That happens in poorly controlled diabetes producing ketones, in situations where tissues are short of oxygen and generate lactic acid, in chronic kidney disease where acid cannot be excreted properly, and in prolonged diarrhoea, which flushes bicarbonate out through the gut. A rise usually reflects the opposite: acid lost through repeated vomiting, or bicarbonate retained by the kidneys to offset carbon dioxide that chronically lung disease prevents from being cleared. Neither direction is a diagnosis by itself, but both direct your doctor's attention efficiently.
Doctors order this test to evaluate acid-base imbalances, monitor kidney function, and assess conditions such as diabetic ketoacidosis, chronic diarrhea, or respiratory failure.
Bicarbonate is the simplest routine blood measure of whether your body's acid-base regulation has drifted in one direction or the other.
The kidneys manage bicarbonate directly, so a persistently low level is one of the recognised signs that chronic kidney disease is affecting metabolism.
Long-standing lung disease and repeated vomiting both shift bicarbonate in characteristic directions, which helps explain an unwell patient's biochemistry.
In diabetes, kidney disease or diuretic treatment, tracking bicarbonate helps your doctor see whether management is keeping the balance stable.
Reasons your doctor may request the Bicarbonates (CO2) test
Your doctor may order this test for any of the reasons below. Some are routine checks, others follow specific symptoms or an earlier result.
Routine electrolyte testing
Part of a routine electrolyte or metabolic panel during a general health check.
Fluid loss, diabetes & breathing
Poorly controlled diabetes, particularly with thirst, drowsiness or rapid breathing.
Prolonged vomiting or diarrhoea, or another cause of significant fluid loss.
Chronic lung disease, or unexplained breathlessness and confusion.
Kidney disease & medication
Known or suspected kidney disease being assessed or monitored.
Ongoing treatment with diuretics, antacids or other medicines that affect acid-base balance.
No fasting window — pick any slot that suits you, online or on WhatsApp.
A DHA-licensed nurse collects your sample at home or in the office — free home collection.
A physician-reviewed, easy-to-read report lands securely by WhatsApp and email.
Bicarbonate buffers the blood and reflects acid-base balance.
Ranges are a guide — your physician interprets your result alongside your symptoms and history.
What a higher result can point to
- Repeated vomiting or loss of stomach contents, which removes acid from the body.
- Diuretic treatment, which increases the loss of acid and chloride through the kidneys.
- Chronic lung disease with retained carbon dioxide, prompting the kidneys to hold on to bicarbonate in compensation.
- Excess mineralocorticoid activity, as in primary aldosteronism or certain adrenal disorders.
- Significant dehydration, which concentrates the blood.
- Heavy or prolonged use of antacids and other alkali-containing preparations.
What a lower result can point to
- Ketone production in poorly controlled diabetes.
- Lactic acid accumulation when tissues are short of oxygen, as in severe infection or circulatory failure.
- Chronic kidney disease, where acid can no longer be excreted efficiently.
- Prolonged diarrhoea, which loses bicarbonate directly through the bowel.
- Rapid breathing from anxiety, pain, fever or altitude, with the kidneys compensating by shedding bicarbonate.
- Certain medicines, including some used for glaucoma, epilepsy and migraine.
These are possibilities, not diagnoses. A single value outside the reference range is interpreted alongside your symptoms, history and other tests — your doctor decides what it means for you.
What this test cannot tell you
- Carbon dioxide escapes from a sample tube that is left open or processed slowly, which lowers the reported value artificially.
- The result shows which direction the balance has moved but not the underlying cause, so it is read with the other electrolytes and the clinical picture.
- It cannot separate a primary metabolic problem from the body's compensation for a breathing problem; that needs an arterial blood gas.
- A value within the usual range does not exclude a disturbance where two opposing processes are cancelling each other out.
Risks of the blood draw
- Mild bruising or brief soreness where the needle went in.
- Occasional lightheadedness, which settles after a few minutes of rest.
- Bleeding or infection at the site, which is rare with sterile single-use equipment.
- 1Reported as CO2, this test measures bicarbonate, the body's principal acid buffer.
- 2The lungs and the kidneys jointly control it, so it reflects both systems.
- 3A low value usually indicates acid accumulating or bicarbonate being lost.
- 4A high value usually follows acid loss through vomiting or kidney compensation for retained carbon dioxide.
- 5It is interpreted alongside sodium, potassium and chloride rather than on its own.
Frequently Asked Questions
Everything you need to know about the Bicarbonates (CO2) test. Can't find what you're looking for?
Talk to our team→The test reports total carbon dioxide content in the blood, and the great majority of that is carried as bicarbonate rather than dissolved gas. In practice the two labels are used interchangeably for this measurement, which is why the result sheet can be confusing.
It generally indicates that acid is building up or bicarbonate is being lost. Ketones in poorly controlled diabetes, lactic acid in severe illness, reduced acid excretion in kidney disease and prolonged diarrhoea are the usual explanations, and your doctor will use your symptoms and other results to tell them apart.
Yes, over time. Sustained rapid breathing blows off carbon dioxide, and the kidneys respond by letting bicarbonate go, which lowers the level. In chronic lung disease the opposite happens: carbon dioxide is retained and the kidneys hold on to bicarbonate to compensate.
It can. Carbon dioxide gradually escapes from blood in a tube that is left open or is slow to reach the analyser, and the reported bicarbonate falls as a result. If a value looks out of keeping with how you feel, your doctor may simply repeat it.
This test measures the level of bicarbonate in your blood, which helps maintain the body's acid-base balance. It is commonly part of an electrolyte or metabolic panel and requires a simple blood draw.
Doctors order this test to evaluate acid-base imbalances, monitor kidney function, and assess conditions such as diabetic ketoacidosis, chronic diarrhea, or respiratory failure.
No, fasting is not required for the Blood Bicarbonate (CO2) test, so you can eat and drink normally beforehand.
The Blood Bicarbonate (CO2) test uses a blood sample, collected quickly by our DHA-licensed phlebotomist with minimal discomfort.
Results for the Blood Bicarbonate (CO2) test are typically ready within 12 hours. You will receive a secure digital report, and your Smart Report highlights anything outside the normal range.
The Blood Bicarbonate (CO2) test is AED 70, which includes free home sample collection and a physician-reviewed report. You can also build a custom panel and pay only for the markers you choose.
Yes. A DHA-licensed phlebotomist can collect your sample at home or the office anywhere in Dubai at no extra cost, 7 days a week. See how it works.
It is commonly chosen by adults & teens. If you are not sure it is right for you, our care team is happy to advise.
Add the Blood Bicarbonate (CO2) test to your cart and complete the short booking wizard, choosing home collection or a lab visit. Guest checkout lets you book without creating an account.
Yes. It is processed at our EIAC-accredited laboratory (ISO 15189:2022) under DHA license 0046381 and verified by board-certified pathologists.
Every report includes reference ranges and plain-language notes. If you have questions, our care team can arrange a clinician review — just get in touch.
Absolutely. Add it to a curated health package or bundle it with any of our 160+ biomarkers, often from a single sample in one visit.