Strep Test: Rapid

en españolPrueba estreptocócica rápida

What It Is

A rapid strep test involves a quick throat swab. Within minutes, the test can show the presence of group A streptococcus bacteria, which can cause strep throat and other infections (including scarlet fever, abscesses, and pneumonia).

Strep throat is a bacterial infection that affects the back of the throat and the tonsils, which become irritated and swollen, causing a sore throat that's especially painful when swallowing. Your child may get white or yellow spots, or a coating on the throat and tonsils, and the lymph nodes in the neck may swell and become tender to touch.

Strep throat is most common among 5- to 10-year-olds. Up to 20% of schoolchildren may be carrying the bacteria but show no symptoms, though they can still spread the infection. In kids, strep throat may cause body aches, headaches, stomachaches, nausea, vomiting, or listlessness. The infection usually doesn't include other cold symptoms (such as sneezing, coughing, or a runny or stuffy nose).

Most sore throats in kids are caused by viral infections, which clear up on their own without antibiotic treatment. While strep throat sometimes can go away within a few days without treatment, doctors prescribe antibiotics to prevent related complications that can be serious, such as rheumatic fever.

Why It's Done

The rapid strep test is done to help quickly see whether a child's sore throat is caused by a strep infection vs. other germs (usually viruses) that don't require antibiotic treatment.

A doctor may do a rapid strep test done if a child:

• has symptoms of a strep throat infection and doesn't have symptoms typical of a virus infection
• has a sore throat and has been exposed to someone known to have a strep throat, or if there are many strep throat cases in the community

Sometimes, doctors do a throat culture instead of a rapid strep test. A throat culture is more accurate than a rapid strep test, but the results take longer (2-3 days) to come back.

Preparation

Encourage your child to stay still during the procedure so the health professional can collect enough secretions for an accurate test. Be sure to tell your doctor if your child has taken antibiotics recently, and don't have your child use mouthwash before the test as it may affect test results.

The Procedure

A health professional will ask your child to tilt his or her head back and open his or her mouth as wide as possible. Your child's tongue will then be pressed down with a flat stick (tongue depressor) to clearly examine the mouth and throat. A clean, soft cotton swab will be lightly brushed over the back of the throat, around the tonsils, and over any red or sore areas to collect a sample.

Sometimes, two swabs will be used so the second swab can be sent for a throat culture if the rapid strep test results are negative. Swabbing will last only a few seconds. The secretions on the swab are then analyzed in the office or a laboratory.

You might want to hold a young child on your lap during the procedure to prevent him or her from moving around, which could make it difficult for the health professional to get a good sample.

What to Expect

Your child may feel like gagging when the swab touches the back of the throat. If your child's throat is sore, the swabbing may cause slight pain temporarily.

Getting the Results

Test results are usually available in about 15 minutes. If the rapid strep test indicates a strep infection, the doctor usually will prescribe antibiotics. Keep in mind, though, that up to a third of negative rapid strep test results are false (meaning someone actually has a strep throat infection even though the rapid strep results were negative). A throat culture may then be done to ensure accuracy.

Risks

Throat swabs can be uncomfortable, but no risks are associated with a rapid strep test.

Helping Your Child

Explaining the test in terms your child can understand might help ease any fear. During the test, encourage your child to relax and stay still so the health professional can easily swab the throat and tonsils.

If You Have Questions

If you have questions about the rapid strep test, speak with your doctor.