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Streptococcus Group A Rapid Antigen Test (Throat Swab)

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

This test checks for the presence of Group A Streptococcus bacteria in your throat, which can cause strep throat or other infections.

Quick summary

["A positive result helps confirm strep throat and guides treatment decisions quickly."]

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

Key facts at a glance

LOINC
78012-2
Short code
S pyo Ag Throat Ql IA.rapid
Synonyms
S pyo Ag Throat Ql IA.rapid
Category
coagulation
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
ia-rapid
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

How the Test Works

A swab is gently placed in your throat to collect a sample. The test detects specific proteins (antigens) from Group A Streptococcus bacteria using a rapid immunoassay method. Results are typically available in 15 minutes.

What to Expect Before the Test

You may experience mild discomfort from the throat swab, but it usually takes only a few seconds. Avoid eating or drinking for 15–30 minutes before testing if instructed, as it may affect accuracy.

What the Results Mean

A positive result indicates likely Group A Streptococcus infection. A negative result means the bacteria were not detected in this sample, but other causes of throat symptoms (like viruses) could still be present.

When to Follow Up

If you have symptoms like sore throat, fever, swollen lymph nodes, or rash, follow your healthcare provider’s advice. A positive result often requires antibiotics to clear the infection.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Group A Streptococcus is a common cause of strep throat and can lead to complications like rheumatic fever if untreated. Rapid testing helps providers act quickly to prevent spread and reduce risks.

Short name

Rapid Group A Strep Test

Frequently asked questions

Why did my doctor order this test?
Your doctor may recommend this test if you have symptoms like sudden sore throat, fever, or swollen tonsils, especially if antibiotics are needed quickly. It helps rule out strep throat before prescribing treatment.
What happens if my test is positive?
A positive result means you likely have strep throat. Your doctor will likely prescribe antibiotics (such as penicillin) to treat the infection and prevent complications. Rest and hydration are also important.
Can I still spread strep throat if my test is negative?
Yes, if you have symptoms but test negative, you may still carry Group A Streptococcus or have a viral infection. Stay home from school/work, avoid close contact with others, and follow your doctor’s advice for monitoring.
  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