Strep Test Q&As

What is the Strep Test?

The Rapid strep test (RST), or rapid antigen detection test (RADT), is a rapid diagnostic test that is widely used in clinics to assist in the diagnosis of bacterial pharyngitis caused by group A streptococci (GAS), sometimes termed strep throat.

How to do a rapid strep test ?
Strep A Test How-To

1. Collect the throat swab specimen with the throat swab that is provided in the kit. Swab the posterior of the pharynx (throat), tonsils and other inflamed areas.

2. Testing should be ideally performed immediately after the samples have been collected. Swab samples may be stored at room temperature for up to four hours prior to testing.

3. If a culture is desired, lightly roll the swab tip onto a Group A selective (GAS) blood agar plate before using the swab in the Areta Strep-A Swab test.

4. Add 5 drops of the Reagnant A and B to the tube.

5. Place swab in tube and swirl 10 times and leave in the solution 1 minute.

6. Extract swab afterwards, expunging any excess liquid in the extraction tube.

7. Cap the tube and mix contents by gently swirling.

8. Remove test strip from sealed pouch and dip into specimen not exceeding the max line.

9. Take the strip out after 5 seconds and lay flat in a clean, dry, non-absorbent surface.

10. Wait for 10 minutes and read the results. Do not read after 20 minutes.

What is group A streptococcus (GAS)?

Group A streptococcus (STREP-toe-KAH-kiss) is a bacterium often found in the throat and on the skin. People may carry this bacterium in the throat or on the skin and have no symptoms of illness. Most GAS infections cause relatively mild illness such as "strep throat," or impetigo. On rare occasions, these bacteria can cause other severe and even fatal diseases.

How do I interpret the results?
  • Positive result will indicate visible color bands in the test and control region.
  • Negative result will indicate a visible color band only in the control region.
  • Invalid result will indicate no visible lines in either region or a visible line in the test region.
What can affect the results?
  • Taking antibiotics recently may prevent the growth of an infection in the culture.
  • Contamination of the throat culture sample by other types of bacteria from the mouth.
  • Using antiseptic mouthwashes before the culture is taken.

Tip: If you are using to screen clean from Strep-A once taken a prescribed Antibiotic, a positive result can still appear for several days after the last dosage of antibiotic was administered.

What if the result is negative, but I have symptoms similar to Strep A?

You may want to test a throat culture done at the doctor's office to confirm. Symptoms similar Strep A can be viral related. The Strep A tests only for Strep A, which is a bacterial infection and a positive result requires Antibiotic treatment.

What is the expiration date for the Strep-A test strips?

This will vary per batch. All of the tests start out with a 2 year expiration date from the manufacturer. Each test comes with a visible expiration date on the box and product.

How can I test the accuracy of the test strips?

Perform an optional control test, steps are located in the manual. A control test can show what an ideal test would look like as a positive or a negative result. Read the results within 10-20 minutes. Tip: Use control + or control - to mix with reagent A & B drops to avoid improper testing. No throat culture is needed.