Other names: C1 Esterase Inh. Ag
Optimal Result:
19 - 37 mg/dL.
C1 Esterase Inhibitor Antigen, often abbreviated as C1-INH Ag, is a blood test that measures the amount of C1 esterase inhibitor protein in your blood. This protein plays a crucial role in regulating parts of your immune system and the complement system, which helps fight infections and control inflammation.
C1 esterase inhibitor helps keep your immune system in balance by preventing excessive activation of the complement pathway, a part of your immune defense. If you don’t have enough of this protein, or if it’s not working properly, it can lead to uncontrolled inflammation and swelling in the body.
This test is most commonly used to help diagnose Hereditary Angioedema (HAE) Type I — a rare but serious genetic condition that causes sudden, recurrent episodes of swelling in the face, throat, abdomen, limbs, or airway.
It may also be used to evaluate:
Acquired angioedema (AAE), which can occur in adults due to other conditions like lymphomas or autoimmune disorders.
Unexplained recurrent swelling or abdominal pain without allergic triggers.
| C1-INH Antigen Level | Possible Interpretation |
|---|---|
| Low | Suggests Type I Hereditary Angioedema (HAE) or Acquired Angioedema (AAE) |
| Normal or High | If symptoms persist, a functional C1-INH test may be needed to check whether the protein is working properly (to rule out Type II HAE) |
It’s important to interpret this result alongside C4 levels and possibly a C1-INH functional assay for a full diagnostic picture.
Swelling of the face, lips, tongue, throat, or extremities
Abdominal pain, cramping, or bloating
Difficulty breathing during swelling episodes
No response to standard allergy medications (like antihistamines or steroids)
A blood sample is drawn, usually from a vein in your arm. No special preparation is needed in most cases.
Doctors often order additional tests alongside C1-INH Ag for a more complete diagnosis:
C1 Esterase Inhibitor, Functional – Measures whether the protein works properly
Complement C4 levels – Often low during HAE attacks
C1q level – May help differentiate hereditary vs. acquired angioedema
The C1 Esterase Inh. Ag (Antigen) test measures how much of this critical immune-regulating protein is in your blood. A low result can point to Type I Hereditary Angioedema, a condition that causes episodes of swelling that can be life-threatening if untreated. If your antigen level is normal but symptoms continue, your doctor may order further tests to check how well the protein is functioning.
Elevated levels of C1 esterase inhibitor antigen (C1-INH Ag) are uncommon and, by themselves, are usually not clinically significant. This test is most often used to detect low levels of the protein in conditions such as Hereditary Angioedema (HAE) Type I or Acquired Angioedema (AAE). However, if your C1-INH Ag levels are above the reference range, here’s what it may mean:
C1-INH is a serine protease inhibitor and can act as an acute-phase protein. Its levels may rise modestly in response to:
Inflammation
Infection
Tissue injury
Autoimmune activity
However, this increase is generally less pronounced and less consistent than with other acute-phase proteins like C-reactive protein (CRP) or serum amyloid A (SAA). In these cases, elevated C1-INH Ag reflects a nonspecific immune response.
Rarely, elevated C1-INH Ag may reflect a compensatory increase in production due to chronic activation of the complement or contact systems. In Hereditary Angioedema Type II (HAE-II), for example:
C1-INH Ag levels may be normal or even elevated (sometimes significantly above the reference range)
The protein is dysfunctional and does not work properly
This paradoxical elevation can serve as a clue for HAE-II, especially when accompanied by low C4 levels.
Some individuals may naturally have higher C1-INH Ag levels due to genetic variation or minor laboratory fluctuation, without any clinical consequence.
As with any laboratory test, spurious elevation can occur due to:
Sample handling or processing issues
Concurrent medications
Technical variability in assay methods
An elevated C1-INH antigen level does not guarantee that the protein is functioning correctly. For example, in HAE-II:
C1-INH Ag may be normal or high
The protein is dysfunctional
Functional testing is essential to determine whether the C1-INH protein is working as it should.
If your C1-INH Ag is elevated, your clinician may consider:
Ordering a C1-INH functional assay to assess protein activity
Testing C4 and C1q levels to evaluate complement system activity
Low C4 with normal C1q: Suggests HAE-II
Low C4 with low C1q: Suggests AAE
Reviewing symptoms, medical history, and other inflammatory markers
Elevated C1 esterase inhibitor antigen levels are usually not a cause for concern on their own and are most often seen in the context of inflammation, protein dysfunction (as in HAE-II), or laboratory variation. They are not associated with angioedema unless accompanied by symptoms and other abnormal complement markers. If elevated C1-INH Ag is found, further functional and complement testing is recommended to guide diagnosis and management.
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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.
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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.
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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.
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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.
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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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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 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.
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