A streptococcal screen, also called a rapid Streptococcus screening test or rapid strep screen, is a test that determines if you have a type of bacteria called group A Streptococcus in your throat. This bacterium causes an infection called streptococcal pharyngitis, which is commonly known as strep throat.
Streptococcal infections are very common, especially in children between the ages of 3 and 15. The infection is spread by contact with infected mucus or saliva.
Your doctor will often recommend a rapid strep screening test if you have a sore throat and fever. Other signs of a strep infection include:
- difficulty swallowing
- a lack of appetite
- low energy level
- tender or swollen lymph glands in the neck
In some cases, people with a strep infection have a pink skin rash that feels like sandpaper. Because strep is less common in adults, your doctor may not order a rapid strep screening unless you have a combination of a severe or recurrent sore throat, fever, and swollen lymph nodes in your throat.
A rapid screen strep test is simple and can be done in your doctor’s office. You don’t need to prepare. However, try to avoid using mouthwash before the test because it can interfere with results.
Your doctor will examine your mouth to check for red, swollen areas or other signs of infection. Your doctor will ask you to open your mouth wide and will use a wooden tongue depressor to hold your tongue down.
Then, your doctor will take a cotton swab and brush it against the back of your pharynx, or throat, to obtain a sample for the test. They may do this twice to get more accurate results. The swabs will be tested with a kit to see if group A streptococcus bacteria are present.
The test isn’t painful, but it does cause minor discomfort. The position of the swab may cause a gag reflex, thereby triggering a reflex that makes you want to regurgitate. If your child is having a rapid strep screen, it’s a good idea to hold their arms or have them seated on your lap. You may need to help restrain your child.
The rapid screen strep kit takes about 10 minutes to process. If the test is positive, you have group A streptococcus bacteria in your throat and you probably have an infection. In that case, your doctor will write a prescription for a 5- to 7- day course of antibiotics. If it’s negative, you don’t have the bacteria in your throat and no antibiotics are needed.
The rapid strep screen is fairly reliable, but antibiotics and antiseptic mouthwash can affect the test results. Tell your doctor if you’re taking antibiotics.
In some cases, if you have symptoms of a strep infection but your test comes back negative, your doctor may order a throat culture. A throat culture is similar to a rapid screen test, but the processing of the sample is more in-depth. It’s also more expensive and takes longer to get results. It can take up to 72 hours because the swabs are cultured, which means that any bacteria on them are allowed to grow. A throat culture can confirm the presence of group A streptococcus bacteria, and it’s generally considered to be more accurate than a rapid strep screen.
It’s also important to note that a rapid strep screen test only screens for group A streptococcus, which is one type of bacteria. This means that if your test is negative, you could still have an infection from another type of bacteria or virus.
The test is easy and quick. It has no side effects or risks. If you test positive for strep, your doctor will likely prescribe antibiotics and recommend that you drink warm fluids and gargle with salt water.
If you test negative for strep but still have a sore throat, your doctor may look at other possible causes, including infections from other bacteria or viruses.
If a strep infection is left untreated, it can lead to more serious medical conditions including:
See your doctor right away if you have any symptoms of strep.