Other names: Carbon Dioxide, Total, Bicarbonate (HCO₃⁻), Total CO₂, CO₂ (Serum), CO₂, Carbon Dioxide (Blood), TCO₂, Serum Bicarbonate, Plasma CO₂
Optimal Result:
20 - 29 mEq/L,
or
20 - 29 mmol/L.
Carbon dioxide (CO₂) is a metabolic waste product produced when the body converts nutrients into energy. In the blood, CO₂ is transported primarily as bicarbonate (HCO₃⁻), which plays a central role in maintaining blood pH within a narrow, healthy range.
Rather than measuring gaseous CO₂ directly, a standard blood test reflects total bicarbonate concentration, making CO₂ an important marker of acid–base balance and electrolyte regulation.
A CO₂ blood test—also called a bicarbonate or total CO₂ test—measures the amount of bicarbonate in the blood. This helps evaluate whether the body is trending toward acidosis (too acidic) or alkalosis (too alkaline) and whether the lungs or kidneys are contributing to the imbalance.
Common alternate names include:
Bicarbonate (HCO₃⁻)
Total CO₂ (TCO₂)
CO₂ content
CO₂ serum test
Bicarbonate acts as a buffering system that stabilizes blood pH. Abnormal levels may signal:
Kidney dysfunction (impaired acid removal)
Respiratory disorders (altered CO₂ exhalation)
Dehydration or fluid imbalance
Metabolic disturbances
Acid–base disorders (acidosis or alkalosis)
For this reason, CO₂ is routinely assessed as part of electrolyte and metabolic panels.
CO₂ testing may be ordered when symptoms suggest acid–base imbalance, including:
Shortness of breath
Nausea or vomiting
Fatigue
Confusion
Rapid or shallow breathing
It is also commonly monitored in individuals with kidney disease, lung disease, diabetes, dehydration, or critical illness.
Clinically, yes:
Bicarbonate (HCO₃⁻) is the primary form of CO₂ in the blood.
The CO₂ test reflects total bicarbonate concentration.
This is why the terms are often used interchangeably in lab reports.
Typical adult reference range:
20–29 mEq/L
Ranges may vary slightly by laboratory. Results outside this range should be interpreted in context and do not automatically indicate disease.
If more precise evaluation is needed, an arterial blood gas (ABG) test may be ordered. ABGs directly measure:
Blood pH
Partial pressure of CO₂ (PaCO₂)
Oxygen levels
Bicarbonate
ABGs are especially useful in respiratory and critical care settings.
Abnormal bicarbonate levels may be linked to:
Metabolic acidosis or alkalosis
Chronic kidney disease
Liver dysfunction
Prolonged vomiting or diarrhea
COPD or other chronic lung diseases
Diabetic ketoacidosis
Severe infections (sepsis)
The CO₂ (bicarbonate) blood test is a core marker of acid–base balance and metabolic health. While abnormal results can indicate serious conditions, many cases are temporary or reversible. Interpretation alongside other electrolytes, kidney markers, respiratory status, and symptoms is essential for accurate diagnosis and management.
Elevated CO₂ levels reflect excess bicarbonate or impaired CO₂ elimination, most often due to metabolic alkalosis or chronic respiratory retention.
Key contributors include:
Dehydration
Chronic lung disease (e.g., COPD)
Prolonged vomiting
Diuretic overuse
Kidney compensation for respiratory disorders
Endocrine conditions such as Cushing’s syndrome
High CO₂ should always be interpreted with chloride, potassium, blood pH, and clinical context before drawing conclusions.
Import lab results from multiple providers, track changes over time, customize your reference ranges, and get clear explanations for each result. Everything is stored securely, exportable in one organized file, and shareable with your doctor—or anyone you choose.
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A low carbon dioxide (CO₂) level on a blood test—most commonly reflecting low bicarbonate (HCO₃⁻)—signals a disruption in the body’s acid–base balance. Depending on blood pH and clinical context, this typically points to either metabolic acidosis or respiratory alkalosis.
Identifying the underlying cause is essential, as low bicarbonate is not a diagnosis itself, but rather a marker of an underlying metabolic, respiratory, renal, or systemic issue.
Low bicarbonate levels may result from increased acid production, impaired acid excretion, or excessive loss of CO₂. Common causes include:
Hyperventilation (excessive CO₂ loss)
Prolonged diarrhea or dehydration
Uncontrolled diabetes (diabetic ketoacidosis)
Kidney dysfunction (reduced acid excretion)
Liver disease
Severe infections or sepsis
Aspirin (salicylate) toxicity or alcohol overdose
Major cardiac events (e.g., large myocardial infarction)
Hyperthyroidism
Severe malnutrition
Low CO₂ + Low pH (< 7.35)
Occurs when excess acid accumulates or the kidneys cannot remove acid efficiently.
Common causes:
Chronic kidney disease
Diabetic ketoacidosis (DKA)
Lactic acidosis (from shock, hypoxia, or severe illness)
Severe or prolonged diarrhea
Liver failure
Sepsis or severe infection
Prolonged hypoxia
Seizures or major metabolic stress
Low CO₂ + High pH (> 7.45)
Results from excessive CO₂ loss due to rapid or deep breathing.
Common triggers:
Anxiety or panic attacks
Fever
Severe pain
Acute illness causing hyperventilation
High-altitude exposure
Certain medications can contribute to reduced bicarbonate or acid–base disturbances, including:
Thiazide diuretics
Potassium-sparing diuretics (e.g., triamterene)
Certain antibiotics (e.g., tetracyclines, nitrofurantoin)
Salicylates (especially at toxic doses)
Medication effects should always be evaluated in the context of kidney function, hydration status, and electrolyte balance.
Request comprehensive testing, including:
Serum electrolytes
Kidney and liver function tests
Blood glucose and ketones (if diabetes is suspected)
Arterial or venous blood gases (ABG/VBG)
Determine whether the disturbance is metabolic or respiratory in origin.
Replace fluids if dehydration or diarrhea is present.
Oral rehydration may be sufficient for mild cases.
Severe dehydration may require intravenous fluids under medical supervision.
Diabetic ketoacidosis: Requires urgent medical treatment with insulin and electrolyte replacement.
Kidney disease: Long-term management may include dietary modification, alkali therapy, or specialist care.
Liver disease: Address contributing factors such as infection, alcohol use, or metabolic dysfunction.
For hyperventilation-related alkalosis:
Practice slow, diaphragmatic breathing
Address pain, fever, or anxiety triggers
Consider stress management or behavioral therapy when appropriate
Review current prescriptions with a healthcare provider.
Adjust dosing or consider alternatives if medications are contributing to acid–base imbalance.
Address malnutrition with adequate caloric and protein intake.
Ensure sufficient intake of potassium and magnesium, which are closely linked to acid–base regulation.
Consider dietitian support if nutritional deficiencies are present.
Repeat bicarbonate, electrolyte, and pH testing as recommended.
Track trends rather than relying on a single value.
Low CO₂ levels can become life-threatening when associated with severe acidosis or systemic illness. Seek urgent care if symptoms include:
Rapid or deep breathing
Confusion or altered mental status
Severe weakness or fatigue
Chest pain or palpitations
Signs of shock (cold, clammy skin; rapid heartbeat)
Low bicarbonate (CO₂) levels indicate a disruption in the body’s acid–base balance—not a standalone diagnosis. Determining whether the cause is metabolic, respiratory, renal, or systemic is critical. With timely evaluation and targeted treatment, many causes are reversible, and early intervention can prevent serious complications.
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Import Lab Results from Any Source
Easily upload lab results from any provider, whether it's a hospital, independent lab, or home testing service. We support PDFs, scanned documents, and JPEGs from patient portals. No need to log in to multiple platforms — everything is centralized in one secure space.
Easily upload lab results from any provider — we support PDFs, scans, and images. Keep all your reports organized in one secure place.
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Every lab result is automatically organized on a chronological timeline, giving you a complete picture of your health journey. Whether you're tracking a condition, managing treatments, or staying proactive, the timeline helps you and your doctor understand how things progress over time.
Every lab result is automatically organized on a chronological timeline, giving you a complete picture of your health journey.
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Whether it's a blood test, GI panel, urinalysis, or something else, lab reports measure numerous biomarkers that reveal what's happening inside your body. Our extensive database covers over 10,000 biomarkers, providing clear, simple explanations of what each result means and how you can take action—no matter your membership level. Say goodbye to confusion and get the insights you need to better understand your health.
Our database covers over 10,000 biomarkers with clear, simple explanations—so you can finally understand your results and what to do next.
Enter Your Lab Reports Yourself — Always Free
Enter Your Lab Reports — Always Free
If you'd like to handle inputting your health data into your account, you can do so with our easy-to-use data entry forms. Our user-friendly form is designed to guide you through the quick and easy submission process, making it simple to keep track of your health metrics. This is available to both Advanced plan and Unlimited plan members.
Our user-friendly form guides you through a quick, simple submission process, making it easy to enter your health metrics.
Add your results anytime with our easy entry form. It's quick, guided, and helps you stay organized — free for all members.
Visualize Your Results
View your lab data through easy-to-read graphs and tables. Quickly spot patterns, track changes, and compare results across different dates — all without digging through multiple reports. You can also select and compare graphs of specific biomarkers side-by-side to better understand how they relate and change over time.
See your lab reports in clear graphs and tables. Spot patterns, track changes, and compare results over time — all in one place.
Export Your Complete Lab History in a Single File
Export Your Complete Lab History
After collecting lab results from different providers, you can download your entire history combined into a single file. Choose from PDF, Excel, or CSV formats to easily review, share, or get a second opinion—no more juggling multiple reports.
After collecting lab results from different providers, you can download your entire history combined into a single file.
Comprehensive Data Entry Service for Your Reports
Data Entry Service for Your Reports
Our inclusive service handles the data entry for your lab reports. Just submit your information and we'll take care of the rest. Advanced plan members receive five reports entered for free, then $15 per report after that. Unlimited plan members receive ten report entries for free, then $15 per report after that.
Our inclusive service handles the data entry for your lab reports. Just submit your information and we'll take care of the rest.
Securely Share With Anyone You Trust
Whether you're working with a doctor, nutritionist, caregiver, or wellness coach, you can securely share your complete lab history by sending an invite link to anyone you trust. You have full control over who sees your information and for how long, ensuring your privacy and peace of mind at every step.
Share your full lab history with your doctor, nutritionist, or coach using a secure invite link.
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I have been using Healthmatters.io since 2021. I travel all over the world and use different doctors and health facilities. This site has allowed me to consolidate all my various test results over 14 years in one place. And every doctor that I show this to has been impressed. Because with any health professional I talk to, I can pull up historical results in seconds. It is invaluable. Even going back to the same doctor, they usually do not have the historical results from their facility in a graph format. That has been very helpful.
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What fantastic service and great, easy-to-follow layouts! I love your website; it makes it so helpful to see patterns in my health data. It's truly a pleasure to use. I only wish the NHS was as organized and quick as Healthmatters.io. You've set a new standard for health tracking!
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As a PRO member and medical practitioner, Healthmatters.io has been an invaluable tool for tracking my clients' data. The layout is intuitive, making it easy to monitor trends and spot patterns over time. The ability to customize reports and charts helps me present information clearly to my clients, improving communication and outcomes. It's streamlined my workflow, saving me time and providing insights at a glance. Highly recommended for any practitioner looking for a comprehensive and user-friendly solution to track patient labs!
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Healthmatters is a personal health dashboard that helps you organize and understand your lab results. It collects and displays your medical test data from any lab in one secure, easy-to-use platform.
With a Healthmatters account, you can:
Professionals can also analyze client data more efficiently and save time managing lab reports.
Healthmatters.io personal account provides in-depth research on 10000+ biomarkers, including information and suggestions for test panels such as, but not limited to:
You can combine all test reports inside your Healthmatters account and keep them in one place. It gives you an excellent overview of all your health data. Once you retest, you can add new results and compare them.
If you are still determining whether Healthmatters support your lab results, the rule is that if you can test it, you can upload it to Healthmatters.
While we work with many popular labs, we welcome reports from lots of other places too.
It's as simple as this: if you can get a test done, you can upload it to Healthmatters and we can interpret results from any lab out there. If laboratories can analyze it, we can interpret it.
If you're on the hunt for a specific biomarker, contact us and we'll add it to our database. Anything from blood, urine, saliva, or stool can be uploaded, understood, and tracked with your Healthmatters account.
The Advanced Plan ($79/year) is perfect for individuals who want ongoing access to their health data. It includes unlimited self-entry of lab reports, visual tracking, custom ranges, result explanations, full account exports, and secure sharing — all with a simple yearly subscription. The plan also includes free data entry of up to 5 reports by our data entry team. You can cancel anytime and restart your plan whenever you're ready — your data will still be there waiting for you. You can also upgrade to the Unlimited Plan at any time, with the cost prorated based on what you've already paid.
The Unlimited Plan ($250 one-time) is also designed for individuals but offers lifetime access with no ongoing subscription. You'll get all the same features as the Advanced Plan, plus free data entry of up to 10 reports by our data entry team, making it a great choice if you prefer a one-time payment and long-term use without yearly fees.
In short:
There are two ways to add your test reports to your Healthmatters account. One option is to input the data using the data entry forms. The other method is to utilize our "Data entry service."
Our data entry forms offer an easy, fast, and free way for you to input the reports yourself. Self-entry allows you to add an unlimited number of reports at no cost. We make the self-entry process user-friendly, providing dozens of templates that pre-populate the most popular laboratory panels and offering instant feedback on entered values.
For those who prefer assistance, we offer a "Data entry service" to help you input your data. Simply attach an image or file of your lab test results, and a qualified team member from our data entry team will add the results for you.
We support various file types, including PDFs, JPGs, or Excel. This service is particularly useful if you have many reports to upload or if you're too busy to handle the data entry yourself.
Our Data Entry Service is for when you don't want to manually type in your lab results yourself. You simply upload your report (PDF, image, or screenshot), and our trained team enters the information into your Healthmatters account for you — accurately and neatly organized, ready to view in graphs, tables, and timelines.
The $15 per report covers the time and care it takes for a real person to review your file, make sure each result is entered correctly, and double-check for accuracy. This ensures your health data is precise and easy to work with — without you having to spend the time doing it yourself.
Prefer to do it yourself? You can always use our free self-entry tool to add results manually — it just takes a bit more time and attention.
For users on the Advanced Plan, the first 5 reports are included free of charge, and each additional report incurs a $15 fee.
Unlimited Plan holders enjoy the entry of 10 reports at no charge. Subsequent reports are subject to a $15 fee per report.
Additionally, users on the Advanced Plan can upgrade to the Unlimited Plan from their account settings.
All professional accounts allow you to import and onboard an unlimited number of clients and their lab results. The distinction between professional plans lies solely in the data entry service.
The Pro Monthly Plus plan is priced at $75 per month and includes a data entry service for five reports each month. Additional reports can be self-entered at no extra cost or, if preferred, you can use our data entry service for an additional fee of $15 per report.
The Pro Monthly plan is priced at $45 per month and does not include a data entry service. Self-entry is free for an unlimited number of reports, and you can opt for the data entry service at a fee of $15 per report.
You also have the option to upgrade to higher monthly or to annual plans, which come with substantial discounts. All upgrades can be done directly from your account.
Simply log in and navigate to your account settings to cancel your subscription. Scroll down to locate the 'Cancel' button at the bottom of the page. Ensure you cancel at least one day before the renewal date to prevent any charges. Once cancellation is requested, the subscription remains active until the conclusion of the current billing cycle.
Our goal has been to make your Healthmatters account as intuitive as possible.
We've crafted multiple ways for you to navigate your data, whether you're glancing at a single report or delving into your historical test reports.
1. Graph View:Dive into a visual journey with our biomarker graphs, showcasing over 40 data points. Combining years of results unveils trends, empowering you to make informed decisions. Our visualization tools make it a breeze to compare and understand changes over time, even if your results are from different labs. A search function and filters simplify the exploration of extensive data, allowing you to focus on what needs attention.
2. All Tests ViewExplore neatly organized reports on a timeline, highlighting crucial details like dates, critical results, and lab/panel names. Each report opens up to reveal in-depth descriptions and additional recommendations for each biomarker. The history of previous results is just a click away, and you can download a comprehensive report for deeper insights. Color-coded and user-friendly, it's designed for easy reading, understanding, and navigation.
3. Table View:For a holistic view of all biomarkers side by side, our table view is your go-to. Results are neatly displayed in a categorized and dated table, ideal for those with an extensive test history. Utilize sorting, filters, and color-coding to enhance your analysis and gain extra insights.
Yes, you can download your information anytime. We offer two easy ways to export your lab data:
This makes it simple to save, back up, or share your health data whenever you need.
Yes, you can print your report. To do so, navigate to "All tests" and open the report you wish to print. You'll find a print button in the right corner of the report. Click on it, and your browser's print window will open. If you prefer to print in a bigger typeface, adjust the scale using the print window settings.
Yes, you can! We highly recommend activating Two-Factor Authentication (2FA) for your account. To do so, please navigate to the "Profile and Security" section of your account, where you will find instructions for activating 2FA.
Yes, you can. When entering values for the biomarker, you will see an "Edit Range" button. Click this button, and you'll have the option to enter a custom range.
A personal account is all about keeping your own lab test results in check. It's just for you and your personal use.
The professional account is designed for health professionals who wish to track and organize their clients' laboratory results.
To learn more about Healthmatters Pro, please refer to the professional page.
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