Strep B Test
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What is Strep B Test?
A Strep B test is a laboratory test that is used to determine the presence or absence of group B Streptococcus (GBS) in a sample of fluid taken from the vagina and rectum of pregnant women. It is usually done during the last month of pregnancy to screen for GBS infection and look for any colonization in the vagina and rectum, which can cause severe infections in newborns. The test is also known as the Strep B vaginal swab test.
Why is a Strep B Test Performed?
A Strep B test is performed to detect the presence of Group B Streptococcus bacteria in pregnant women. GBS is a common bacteria that can be found in the vagina and rectum of a healthy person. It is not harmful to the mother, but if the bacteria is present during delivery, the newborn can become infected. GBS is the leading cause of bacterial infection in newborns, accounting for around 15,000 cases per year in the United States.
Preparation for Strep B Test
No prior preparation is needed for the Strep B test. The test is typically performed while you are in the doctor’s office or hospital.
Procedure for Strep B Test
The procedure for the Strep B test usually involves a pelvic examination and vaginal/rectal swab. Typically a cotton swab is inserted into the vagina and then into the rectum, and is then sent off to the laboratory to determine if any GBS bacteria is present.
Types of Strep B Test
The primary type of Strep B test is the culture-based test. This is a type of laboratory test in which the sample is incubated with nutrients and any GBS present will typically show up as colonies on the plate. There is also a newer rapid antigen test that can identify if GBS bacteria is present in the sample without the need for waiting for colonies to form.
Risks Associated with Strep B Test
The Strep B test is a very safe procedure and there are no known risks or side effects associated with it. The swab is inserted only a few millimeters into the vagina and rectum and can cause only minimal discomfort.
Why is the Strep B Test Performed?
The Strep B test is performed to screen for GBS bacteria during pregnancy. This is important because GBS is the leading cause of severe infections in newborns, such as septicaemia (blood infection) and meningitis (infection of the covering of the brain and spinal cord). Early detection can help to prevent these infections via early treatment.
When do You Need a Strep B Test?
The Strep B test is typically performed between the 35th and 37th week of pregnancy. It is done to assess whether the mother has been colonized by GBS. In most cases, if the test is positive, antibiotics are administered during delivery to reduce the risk of infection in the newborn.
