Anti-Streptolysin O

Other names: ASO Screen

check icon Optimal Result: 0 - 199 IU/ml.

The ASO (Anti-Streptolysin O) test measures the level of antibodies your immune system produces in response to Group A Streptococcus, the bacteria that cause strep throat and several skin infections. This test helps determine whether you recently had a strep infection—even if symptoms were mild or went unnoticed—and is often used to evaluate possible post-streptococcal complications, such as rheumatic fever or post-streptococcal glomerulonephritis, a form of kidney inflammation.

What is Anti-Streptolysin O?
Anti-streptolysin O (ASO) is an antibody directed against streptolysin O, a toxin produced by Group A Streptococcus (Streptococcus pyogenes). ASO—along with anti-DNase B—is one of the main antibodies the immune system creates after a strep infection. Measuring ASO levels in the blood helps show whether your body has mounted a recent immune response to this type of bacteria.

About Group A Streptococcus
Group A Streptococcus is best known for causing strep throat, but it can also lead to skin infections such as impetigo, cellulitis, and pyoderma. Most strep infections are diagnosed early and resolve with appropriate antibiotic treatment.

However, when a strep infection is untreated, not fully treated, or produces few noticeable symptoms, the immune response can sometimes trigger more serious conditions—including rheumatic fever and post-streptococcal glomerulonephritis—particularly in children. While these complications have become less common due to routine testing and early treatment, they still occur and can result in heart inflammation, kidney dysfunction, swelling, and high blood pressure.

The ASO test helps clinicians determine whether these issues may be related to a recent Group A strep infection.

Understanding Your Results
A negative or very low ASO level usually means there has not been a recent streptococcal infection. This is especially reliable if a second sample taken 10–14 days later is also low and if the anti-DNase B test is negative as well.
A small number of people with post-streptococcal complications may not show elevated ASO levels—this is more common in cases of kidney inflammation following a skin-based strep infection.

What does it mean if your Anti-Streptolysin O result is too high?

A high ASO level indicates that your immune system has recently responded to a Group A Streptococcus infection. Elevated results are often seen after strep throat, impetigo, or other strep-related infections. High ASO levels do not diagnose an active infection but suggest that a strep infection occurred within the past weeks or months.
Clinicians may use a high ASO result to help evaluate symptoms such as joint pain, fever, swelling, or kidney issues that may indicate rheumatic fever or post-streptococcal glomerulonephritis. A rising ASO level across two tests taken 10–14 days apart provides even stronger evidence of a recent strep infection.

All Your Lab Results.
One Simple Dashboard.

What does it mean if your Anti-Streptolysin O result is too low?

A low or negative ASO level usually means no recent strep infection. This is especially reliable if a repeat test 10–14 days later is also low.
However, some individuals with post-streptococcal complications—especially kidney inflammation following a skin infection—may not show elevated ASO levels. In these cases, an anti-DNase B test may provide additional information.

Laboratories

Bring All Your Lab Results Together — In One Place

We accept reports from any lab, so you can easily collect and organize all your health information in one secure spot.

lab corp logo
genova diagnostics logo
quest diagnostics logo
dutch test logo
doctors data logo
vibrant america logo
diagnostic solutions logo
zrt laboratory logo
the great plains laboratory logo
cyrex laboratories logo
spectracell logo

Pricing Table

decoration

Personal plans

$15/ month

Complete Plan

Access your lab reports, explanations, and tracking tools.

  • Import lab results from any provider
  • Track all results with visual tools
  • Customize your reference ranges
  • Export your full lab history anytime
  • Share results securely with anyone
  • Begin with first report entered
  • Cancel or upgrade anytime

$250/ once

Unlimited Account

Pay once, access everything—no monthly fees, no limits.

  • Import lab results from any provider
  • Track all results with visual tools
  • Customize your reference ranges
  • Export your full lab history anytime
  • Share results securely with anyone
  • Receive 10 reports entered for you
  • Skip the $15/month subscription — no recurring payments ever

$45/ month

Pro Monthly

Designed for professionals managing their clients' lab reports

  • Import lab results from any provider
  • Track lab results for multiple clients
  • Customize reference ranges per client
  • Export lab histories and reports
  • Begin with first report entered by us
  • Cancel or upgrade anytime

About membership

What's included in a Healthmatters membership

microscope icon Import Lab Results from Any Source

person icon See Your Health Timeline

book icon Understand What Your Results Mean

textbook icon

textbook icon Visualize Your Results

folder icon

folder icon

card icon Securely Share With Anyone You Trust

Let Your Lab Results Tell the Full Story

What Healthmatters Members Are Saying

5 stars rating

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

5 stars rating

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

5 stars rating

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

Use promo code to save 10% off any plan.

Frequently asked questions

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.

  • Individuals who want to track and understand their health over time.
  • Health professionals, such as doctors, nutritionists, and wellness coaches, need to manage and interpret lab data for their clients.

With a Healthmatters account, you can:

  • Upload lab reports from any lab
  • View your data in interactive graphs, tables, and timelines
  • Track trends and monitor changes over time
  • Customize your reference ranges
  • Export and share your full lab history
  • Access your results anytime, from any device

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:

  • The GI Effects® Comprehensive Stool Profile,
  • GI-MAP,
  • The NutrEval FMV®,
  • The ION Profile,
  • Amino Acids Profile,
  • Dried Urine Test for Comprehensive Hormones (DUTCH),
  • Organic Acids Test,
  • Organix Comprehensive Profile,
  • Toxic Metals,
  • Complete Blood Count (CBC),
  • Metabolic panel,
  • Thyroid panel,
  • Lipid Panel,
  • Urinalysis,
  • And many, many more.

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.

shield icon

We implement proven measures to keep your data safe.

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.

gdpr compliance image hipaa compliance image