How long does a culture strep test take

The rapid strep screen is used to test for bacteria called group A streptococcus. Group A streptococcus bacteria cause illnesses, such as strep throat and scarlet fever—a rash that may happen after a case of strep throat. Strep throat and scarlet fever can cause a number of symptoms, particularly a fever and a sore throat. These illnesses are quite contagious and need antibiotics to treat. 

Healthcare providers have two ways to test for group A streptococcus. For the rapid strep screen, your healthcare provider or a nurse takes a sample of cells from your tonsils and back of the throat and tests it right in the healthcare provider's office. You can get your results in as little as 5 minutes. If the rapid strep screen is positive, you have strep throat and no further tests may be needed. 

Why do I need this test?

You may need this test if your healthcare provider suspects that you have strep throat. Symptoms of strep throat can include:

• Sore throat

• Painful or difficult swallowing

• Fever

• Swelling or tenderness of the glands in the neck

• Nausea or vomiting

• Skin rash

• Stomachache

• Headache

• Lack of appetite

• Tonsils that are swollen and red

• Patches of white on the tongue or throat

You may need this test to confirm you have a bacterial infection instead of a viral infection before a healthcare provider will prescribe antibiotics. You may also need this test if the results of a throat culture, which can provide a more accurate diagnosis, are unavailable for a few days. 

What other tests might I have along with this test?

If the rapid strep screen is negative, your healthcare provider may do another test called throat culture to make sure that strep is not the cause of your sore throat and other symptoms. This test also needs a swab of cells from your tonsils or back of the throat. The sample is sent to a lab, where it is grown, or cultured, and tested for strep bacteria. The results are available in about 2 days. Your results will reveal whether you have group A streptococcus. 

Your healthcare provider may also order:

• Influenza (flu) test

• Mononucleosis (mono spot) test

What do my test results mean?

Test results may vary depending on your age, gender, health history, and other things. Your test results may be different depending on the lab used. They may not mean you have a problem. Ask your healthcare provider what your test results mean for you.

Your test results will show whether you have group A streptococcus bacteria in the cells or mucus of your throat. A normal (negative) result will not show any group A streptococcus bacteria. If the test is positive, that means bacteria have been found and you likely have strep throat. 

How is this test done?

The rapid strep screen needs a swab of mucus or cells from the back of your throat. The healthcare provider, nurse, or lab technician will gently swipe the back of your throat with a long cotton swab. A second sample may be taken at the same time to be used in a throat culture if the rapid strep screen is negative. 

Does this test pose any risks?

This test poses no known risks.

What might affect my test results?

Nothing is likely to affect the results of your test, as only the presence of group A streptococcus bacteria should give you a positive result.

How do I get ready for this test?

You don't need to prepare for this test. Be sure your healthcare provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illicit drugs you may use. 

A throat swab culture, or throat culture, is a test commonly used to diagnose bacterial infections in the throat. These infections can include strep throat, pneumonia, tonsillitis, whooping cough, and meningitis.

The purpose of a throat swab culture is to detect the presence of organisms in the throat that could cause infection. For example, the presence of group A streptococcus bacteria (Streptococcus pyogenes) in your throat is a key sign that you may have strep throat.

Streptococcal bacteria are very contagious. They can be spread through airborne droplets. An infected person can easily pass the bacteria on if they cough, sneeze, or share food or drinks. The bacteria can also be picked up from doorknobs or other surfaces and transferred to your nose, mouth, or eyes.

If you have a sore throat and your doctor suspects that you may have strep throat or another bacterial infection, they may order a throat swab culture. The results of the test will help you and your doctor form a diagnosis and a treatment plan.

What Is the Purpose of a Throat Swab Culture?

Most sore throats are caused by a virus. Many sore throats go away within a few days without any treatment, except for possibly cough drops or a few over-the-counter drugs to help relieve any pain or discomfort.

Your doctor will generally order a throat culture test if you have symptoms that suggest strep throat or another infection. Redness, swelling, and white streaks or pus on the tonsils as well as red spots in the roof of the mouth are signs of infections. These signs don’t indicate whether the infection is viral or bacterial, so a throat swab is necessary. Strep throat is very contagious, so it’s important that it is caught early.

How Can I Prepare for a Throat Swab Culture?

Antiseptic mouthwash should be avoided before this test. You should also tell your doctor if you have been taking any antibiotics because this could affect the test results.

If your child is undergoing the examination, you should ask them to remain still. You may need to help gently restrain them.

How Is a Throat Swab Culture Performed?

Your doctor will ask you to open your mouth and tilt your head back. If necessary, your doctor may use a tongue depressor. This can help your doctor have a better view of the back of your throat. They will then rub a sterile cotton swab across the back of your throat, your tonsils, and any other sore areas for a few seconds. The swab will collect a sample of the secretions being produced in the back of your throat.

The sample your doctor collects is taken to a laboratory. It will be put on a plate that allows any bacteria on it to grow. The process of growing the bacteria in the sample is called a culture. Chemical tests are conducted on the cultured sample in order to determine if there are any harmful bacteria, and what type of bacteria are present. It usually takes a couple of days to culture the bacteria so you may have to wait some time to receive your test results.

There are no risks or complications associated with a throat swab culture. The test may cause momentary gagging because the back of the throat is a sensitive area, but it shouldn’t be painful.

What Can I Expect After the Test?

It can take several days for the results of a throat culture to be ready. Once the sample has been cultured and the bacteria has been analyzed, your doctor will be in touch to talk about your results.

A negative throat swab culture means that no infectious bacteria are present in your throat. A positive test indicates the presence of streptococci (the bacteria that causes strep throat) or other bacteria. If the test result is positive, the results can be used to determine which bacteria are causing the infection. Once your doctor knows what is causing the infection, you can figure out a treatment plan.

In order to address a bacterial infection, your doctor will most likely prescribe an antibiotic. Penicillin and amoxicillin are two commonly prescribed drugs. Some younger children may have a hard time swallowing a pill, or may be experiencing vomiting, so penicillin can be injected if necessary.

Your doctor may suggest over-the-counter drugs, such as ibuprofen or acetaminophen, to help relive throat pain or reduce fever. Most people start to feel better after a day or two, but if symptoms continue to persist after 48 hours you may need to contact your doctor again.

The Takeaway

Throat swab cultures are very effective tools for identifying infections that affect the throat. A throat culture will determine if there is a bacterial infection, and if so, what’s causing it. Once you know what’s causing your sore throat, you and your doctor can decide on the best treatment options for you.

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