Skip to content

Rapid Streptococcal Group A (Group A Streptococcus) Antigen Test (Throat Swab)

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

This test checks for Group A Streptococcus bacteria, which can cause strep throat or other infections. It uses a throat swab to detect bacterial antigens quickly, often within minutes.

Quick summary

["A fast way to identify strep throat caused by Group A Streptococcus bacteria."]

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

Key facts at a glance

LOINC
6556-5
Short code
Deprecated S pyo Ag Throat Ql EIA
Synonyms
Deprecated S pyo Ag Throat Ql EIA
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
eia
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your healthcare provider may recommend this test if you have symptoms like sore throat, fever, swollen lymph nodes, or difficulty swallowing. It helps rule out strep throat, which can lead to complications if untreated.

How the Test Works

A swab is gently placed in your throat to collect a sample. The swab is then tested for Group A Streptococcus antigens using a rapid immunoassay method, which provides results in about 5–15 minutes.

What to Expect Before the Test

No special preparation is needed. You may brush your teeth or rinse your mouth with water before the test to avoid interfering with the swab. Avoid eating or drinking for 30 minutes before the procedure if instructed.

What to Expect During the Test

The test is quick and painless. You may feel a slight tickle or mild discomfort, but it usually doesn’t cause significant discomfort. The swab is inserted gently and removed quickly.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Strep A Throat Swab Test

Frequently asked questions

How long does the test take?
The test itself takes only a few minutes, but the results are typically available within 5–15 minutes. Your healthcare provider will discuss the results with you.
What are the symptoms of strep throat?
Common symptoms include sudden sore throat, fever, swollen tonsils with white patches, red or swollen throat, swollen lymph nodes in the neck, and difficulty swallowing. Some people may also experience a rash or headache.
Can I eat or drink before the test?
Avoid eating or drinking for 30 minutes before the test if your provider recommends it. Otherwise, you can brush your teeth or rinse your mouth with water to clean your throat.
  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