Group B Streptococci (GBS) Swab test

Group B Streptococci (GBS) or Streptococcus agalactiae are among the most frequent causes of life-threatening infectious in neonates. Between 5% and 30% of all pregnant women are colonized with GBS. Several recent studies have shown that the intrapartum treatment of GBS-colonized women significantly reduces the incidence of GBS-caused sepsis. The US Center for Disease Control and Prevention (CDC) recommends routine examination for Group B streptococcus between the 35th and the 37th week of pregnancy. A CDC study has shown that routine examinations is 50% more effective than the use of antibiotics for pregnant women with clinical risk factors. 

Standard culture methods require 24 to 48 hours, and the results may not be available soon enough for efficient treatment. Thus, methods utilizing more rapid screening techniques are required.


Biologic. material Category Test duration Category

 vaginal or rectal swaps

IVD Other 10 min Prenatal

The Strep B Rapid Test Device (Swab) detects Group B Streptococcus antigens through visual interpretation of color development on the internal strip. Anti-Strep B antibodies are immobilized on the test region of the membrane. During testing, the specimen reacts with polyclonal anti-Strep B antibodies conjugated to colored particles and precoated onto the sample pad of the test. The mixture then migrates through the membrane by capillary action, and interacts with reagents on the membrane. If there is sufficient Strep B antigen in the specimen, a colored band will form at the test region of the membrane. The presence of this colored band indicates a positive result, while its absence indicates a negative result. The appearance of a colored band at the control region serves as a procedural control, indicating that proper volume of specimen has been added and membrane wicking has occurred.