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 (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.
A doctor will typically 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 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 most doctors’ offices and health care clinics. You do not need to prepare in advance. Before the test, 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 (throat) to obtain a sample for the test. He or she may do this twice in order to get results that are more accurate. The swabs will then be tested with a kit to see if group A streptococcus bacteria is present.
The test is not painful, but it does cause minor discomfort. The position of the swab may cause a gag reflex. If your child is having a rapid strep screen, it is a good idea to hold this or her arms or have him or her seated on your lap, as you may need to help restrain your child.
The rapid screen strep kit takes about 15 minutes to process. If the test is positive, you have group A streptococcus bacteria in your throat and may have an infection. If it is negative, you do not have the bacteria in your throat.
The rapid strep screen is fairly reliable. However, antibiotics and antiseptic mouth wash can affect the test results. If you are taking antibiotics, make sure to tell your doctor. If you know you will be tested soon, avoid using mouthwash, as it may lead to a false negative test result.
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 is also more expensive and takes longer to get results 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.
It is also important to note that a rapid strep screen test only screens for one type of bacteria: group A streptococcus. 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, quick, and 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 such as streptococcal pneumonia, ear infections, meningitis, kidney inflammation and rheumatic fever. If you have any symptoms of strep, consult your doctor promptly.