Other names: Carbon Dioxide, Total
Optimal Result:
20 - 29 mEq/L,
or
20 - 29 mmol/L.
Carbon Dioxide (CO2) is a natural byproduct of your body’s metabolism. As your body breaks down nutrients for energy, CO2 is produced and transported through the bloodstream—mostly in the form of bicarbonate (HCO3)—to the lungs, where it is exhaled. In healthy individuals, CO2 levels in the blood remain within a stable, normal range.
CO2 plays a critical role in maintaining your body's acid-base balance (pH). It acts as a buffer to keep your blood from becoming too acidic or too alkaline. As an electrolyte, CO2 works alongside other key electrolytes like sodium, potassium, and chloride to maintain cellular stability and fluid balance.
A CO2 blood test (also called a bicarbonate test, total CO2 test, or CO2 content test) measures the amount of carbon dioxide in your blood, primarily in the form of bicarbonate. This test helps assess your acid-base balance and electrolyte levels, and may indicate whether there is an underlying condition affecting your lungs, kidneys, or metabolic function.
Bicarbonate (HCO3) test
Total CO2 (TCO2)
CO2 content test
CO2 serum test
Carbon dioxide content
Maintaining the right level of carbon dioxide is essential for healthy body function. Abnormal CO2 levels—either too high or too low—can signal a range of health conditions such as:
Respiratory issues
Kidney dysfunction
Metabolic imbalances
Dehydration
Acidosis or alkalosis
The test is often part of a comprehensive metabolic panel (CMP) or electrolyte panel, which also checks sodium, potassium, and chloride levels.
Your healthcare provider may order a CO2 test if you’re experiencing symptoms of a pH imbalance or electrolyte disorder, including:
Shortness of breath
Nausea or vomiting
Fatigue
Breathing difficulties
CO2 levels may also be monitored regularly if you’re undergoing oxygen therapy, certain surgeries, or treatments for chronic lung or kidney conditions.
While they’re often used interchangeably, there is a subtle difference:
Bicarbonate (HCO3) is the main form of carbon dioxide in your blood.
The CO2 blood test actually measures total bicarbonate levels.
This is why the terms CO2 test and bicarbonate test usually refer to the same lab measurement.
Normal carbon dioxide levels in the blood typically range from:
20 – 29 milliequivalents per liter (mEq/L) for adults
However, what's considered "normal" can vary slightly by lab. A CO2 result outside the reference range does not always mean there’s a serious health issue—factors like dehydration, medications, or temporary illness may affect levels.
In some cases, your doctor may order an arterial blood gas (ABG) test to get more precise measurements of CO2, bicarbonate, pH, and oxygen levels. Unlike a standard blood test taken from a vein, an ABG sample is drawn from an artery and is particularly useful in evaluating lung function and respiratory conditions.
Too low or high bicarbonate levels can be associated with:
Metabolic acidosis (too much acid in the body)
Metabolic alkalosis (too much base)
Kidney disease
Liver failure
Diarrhea or vomiting
Chronic obstructive pulmonary disease (COPD)
Eating disorders like anorexia
Your healthcare provider will interpret your CO2 level alongside other test results and symptoms to identify the root cause.
The carbon dioxide (CO2) blood test is a quick and effective tool for assessing acid-base status and electrolyte balance in your body. It’s often part of broader metabolic testing and is especially important for people with respiratory, kidney, or metabolic concerns.
If your test results are outside the normal range, follow up with your doctor. The results must be interpreted in context, alongside other lab values and clinical symptoms.
University of Rochester Medical Center – Carbon Dioxide (Blood)
Kovesdy CP. Metabolic acidosis and kidney disease. Nephrol Dial Transplant. 2012.
Bijapur MB et al. Central Venous vs. Arterial Blood Gas Analysis. Indian J Crit Care Med. 2019.
Seifter JL, Chang HY. Disorders of Acid-Base Balance. Kidney Dis (Basel). 2017.
If your comprehensive metabolic panel (CMP) shows an elevated level of carbon dioxide (CO2), it could mean there's an imbalance in your body's pH (acid-base) levels. CO2 in this test refers to bicarbonate (HCO3-), which helps keep your blood's pH stable. When CO2 levels are higher than normal, it may indicate certain health issues. Here's what you need to know:
Respiratory Issues
Problems with breathing can affect CO2 levels in your blood. For example:
Slow or shallow breathing (hypoventilation) may cause CO2 to build up in your blood.
Chronic respiratory conditions like COPD can also make it harder for your lungs to remove CO2.
Metabolic Alkalosis
This happens when there’s too much bicarbonate in your blood. Causes include:
Excessive vomiting (which removes stomach acid).
Dehydration or losing fluids for a long time.
Overuse of diuretics (medications that help remove excess water from your body).
Kidney Problems
Your kidneys play a big role in balancing bicarbonate and CO2 levels. If they aren’t working properly—like in chronic kidney disease—they might not remove enough bicarbonate, leading to higher CO2 levels.
Cushing's Syndrome
This condition occurs when your body produces too much cortisol, a hormone that can affect your CO2 levels.
Chronic Lung Conditions
Diseases like chronic obstructive pulmonary disease (COPD) or other lung issues can cause difficulty in removing CO2 from your blood.
If you have high CO2 levels, don’t panic! Elevated CO2 can be caused by many factors, and it’s important to work with your healthcare provider to figure out what’s going on. They might recommend additional tests or ask about symptoms like breathing problems, dehydration, or recent illnesses.
Here are some questions you can ask your doctor:
What could be causing my high CO2 levels?
Do I need more tests?
Are there lifestyle changes or treatments that can help?
An elevated carbon dioxide (CO2) level on a comprehensive metabolic panel (CMP) can indicate an imbalance in the body’s acid-base regulation, potentially pointing to conditions like respiratory or metabolic alkalosis, kidney dysfunction/failure, or respiratory disorders like COPD. The presence of high CO2 levels suggests that the body may be retaining too much bicarbonate, which can disrupt normal pH levels and impact overall health. Next steps should include further investigation by a healthcare provider to determine the root cause. This may involve additional tests such as arterial blood gas analysis, kidney function tests, or respiratory assessments. Treatment will depend on the underlying condition, ranging from managing respiratory function to addressing kidney health or electrolyte imbalances. It’s important to follow up with a healthcare professional to tailor an appropriate treatment plan.
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.
Cancel or upgrade anytime
A low level of carbon dioxide (CO2) in the blood—typically measured as bicarbonate (HCO3-)—can indicate disruptions in your body’s acid-base balance. This imbalance is often a sign of metabolic acidosis or respiratory alkalosis, depending on your blood pH.
Understanding the underlying causes and taking actionable steps to address them is crucial for restoring proper acid-base equilibrium and improving your overall health.
Several health conditions and external factors can cause a drop in blood CO2 levels:
Hyperventilation (rapid breathing that reduces CO2)
Aspirin (salicylate) or alcohol overdose
Diarrhea, dehydration, or severe malnutrition
Kidney dysfunction or liver disease
Heart attack (especially large myocardial infarctions)
Hyperthyroidism (overactive thyroid)
Uncontrolled diabetes (diabetic ketoacidosis)
Sepsis (severe systemic infection)
This occurs when your body produces too much acid or the kidneys cannot remove enough acid. Common causes include:
Chronic kidney disease
Liver failure
Severe diarrhea
Lactic acidosis (from shock, intense exercise, or disease)
Diabetic ketoacidosis (DKA)
Prolonged hypoxia (lack of oxygen)
Seizures or severe infections (sepsis)
This is typically due to excessive CO2 loss from hyperventilation. Triggers include:
Anxiety or panic attacks
Fever
Severe pain
Rapid breathing (hyperventilation syndrome)
Some medications can reduce bicarbonate levels as a side effect:
Methicillin (antibiotic)
Nitrofurantoin (UTI treatment)
Tetracycline (broad-spectrum antibiotic)
Thiazide diuretics (blood pressure/edema control)
Triamterene (potassium-sparing diuretic)
Request tests that include arterial blood gases (ABG), serum electrolytes, kidney function tests, and liver panels.
Identify if the cause is metabolic (acidosis) or respiratory (alkalosis) in origin.
Replenish fluids if dehydration or diarrhea is contributing to bicarbonate loss.
Use oral rehydration solutions (ORS) for mild cases; IV fluids may be needed for severe dehydration.
For diabetic ketoacidosis (DKA): Urgent medical intervention with insulin and electrolyte replacement.
For kidney disease: Work with a nephrologist to manage acid retention.
For liver dysfunction: Address root causes like infections, alcohol use, or fatty liver disease.
Practice controlled breathing exercises (like diaphragmatic breathing) if hyperventilation is causing respiratory alkalosis.
Seek behavioral therapy or stress management techniques if anxiety-induced hyperventilation is a factor.
Review your current medications with your healthcare provider to assess if any are contributing to acid-base imbalances.
Discuss possible alternatives or dosage adjustments if necessary.
For malnutrition-related causes, increase intake of alkalizing foods (leafy greens, vegetables) and consult with a dietitian.
Address electrolyte deficiencies, especially potassium and magnesium, which can exacerbate acid-base disturbances.
Regularly monitor bicarbonate levels, blood pH, and electrolytes to track progress and adjust treatment.
Low CO2 levels can become life-threatening if linked to severe metabolic acidosis, diabetic ketoacidosis, or sepsis. Seek emergency care if you experience:
Rapid, deep breathing
Confusion or altered mental status
Severe fatigue or muscle weakness
Chest pain or palpitations
Signs of shock (cold, clammy skin, rapid heartbeat)
Low bicarbonate (CO2) levels are a sign that your body's acid-base balance is disrupted. Identifying and managing the underlying cause—whether dehydration, organ dysfunction, medication side effects, or respiratory issues—is crucial. Early intervention and lifestyle adjustments can help restore balance and prevent complications.
Laboratories
We accept reports from any lab, so you can easily collect and organize all your health information in one secure spot.
Pricing Table
Choose the plan that fits you — and turn scattered lab reports into clear insights you can finally use.
Pick a plan that fits you — and turn scattered lab reports into clarity.
Personal plans
Professional plan
$15/ month
Access your lab reports, explanations, and tracking tools.
$250/ once
Pay once, access everything—no monthly fees, no limits.
Professional plan
$45/ month
Designed for professionals managing their clients' lab reports
About membership
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.
See Your Health Timeline
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.
Understand What Your Results Mean
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 Complete 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. Complete plan members receive one report 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.
Discover
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.
Anthony
Unlimited Plan Member since 2021
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!
Karin
Advanced Plan Member since 2020
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!
Paul
Healthmatters Pro Member since 2024
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 4000+ 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 Complete Plan ($15/month) is perfect for individuals who want ongoing access to their health data. It includes unlimited lab imports, visual tracking, custom ranges, result explanations, full account exports, and secure sharing — all with a simple monthly subscription. 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 Complete Plan, plus a larger initial data entry allowance (10 reports), making it a great choice if you prefer a one-time payment and long-term use without monthly 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 Complete monthly plan, the first report is entered free of charge, and each additional report incurs a fee of $15.
Unlimited account holders enjoy the entry of ten reports without charge. Subsequent reports are subject to a $15 fee per report.
Additionally, users on the Complete plan can upgrade to a yearly subscription from the account settings. The annual subscription includes a data entry service for five reports.
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.
At HealthMatters, we're committed to maintaining the security and confidentiality of your personal information. We've put industry-leading security standards in place to help protect against the loss, misuse, or alteration of the information under our control. We use procedural, physical, and electronic security methods designed to prevent unauthorized people from getting access to this information. Our internal code of conduct adds additional privacy protection. All data is backed up multiple times a day and encrypted using SSL certificates. See our Privacy Policy for more details.
