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Anti-Streptococcal Nucleic Acid Antibody (Qualitative) - Serum/Plasma

Published: August 9, 2026Updated: August 16, 2026

This test detects antibodies produced in response to certain bacterial infections, often linked to strep throat or other streptococcal infections. It helps determine if your body has mounted an immune response to these bacteria.

Quick summary

["This test may be used to diagnose or monitor infections caused by group A streptococcus."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
17657-8
Short code
ASO Ab Snv-aCnc
Synonyms
ASO Ab Snv-aCnc
Category
coagulation
Sample
fluid
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
2-5 mL
Stability
Room temperature: 2h, Refrigerated: 24h
Hemolysis max
300
TAT
4–24 hours
Order
routine

What This Test Measures

The test looks for the presence of antibodies called anti-streptolysin O (ASO) antibodies in your blood. These antibodies develop after your body fights off a streptococcal infection, such as strep throat or scarlet fever. The test is qualitative, meaning it only tells you whether antibodies are present, not their exact level.

Why It’s Ordered

Your doctor may order this test if you have symptoms like sore throat, fever, rash, or swollen lymph nodes that suggest a streptococcal infection. It can also be used to check if the infection has cleared up or if it’s recurring.

Sample Collection and Preparation

A blood sample is taken from a vein, usually in your arm. The blood is then processed to separate the serum or plasma, which is sent to the lab for testing. This test does not require fasting or special preparation.

What to Expect Before or After the Test

You may experience mild discomfort or bruising at the injection site, but this usually goes away quickly. If you have a bleeding disorder or take blood-thinning medications, let your doctor know before the test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

ASO Antibody Screen

Frequently asked questions

When might I get this test?
Your doctor may recommend this test if you have symptoms like a sore throat, fever, or rash that could be caused by a streptococcal infection, or if you’ve been exposed to someone with such an infection.
What does a positive result mean?
A positive result means your blood contains antibodies that your immune system produced in response to a streptococcal infection. This could indicate you had a recent or past infection, but it doesn’t always mean you’re currently sick. It’s important to discuss your symptoms and test results with your doctor.
Can this test be used to diagnose strep throat?
This test can help support a diagnosis of strep throat, but it’s often used alongside other tests like a rapid strep test or throat culture for a more definitive answer. It’s not always the first test doctors use, especially if symptoms are mild.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy