Overview: Streptococcus Group B Antigen TestIntroduction: The Streptococcus Group B Antigen Test detects Group B Streptococcus to diagnose infections, causing fever or sepsis. Following 2023 ACOG guidelines, it uses immunoassays for high specificity, supporting infection screening. This test is critical for guiding diagnosis, treatment planning, and improving outcomes in bacteriology for patients, particularly pregnant women or newborns, with suspected Group B Streptococcus infections.
Other Names: Group B Strep Antigen Assay, GBS Test.
FDA Status: Laboratory-developed test (LDT), meeting bacteriology standards for diagnostic accuracy.
Historical Milestone: GBS testing began in the 1970s with perinatal infection research. Immunoassay methods improved in the 2000s, enhancing diagnostic precision.
Purpose: Detects Group B Streptococcus antigens to diagnose infections, guides treatment, and evaluates patients with fever or sepsis.
Test Parameters: 1. Group B Streptococcus Antigen
Pretest Condition: No fasting required. Collect swab, vaginal swab, or rectal swab. Report history of fever, sepsis, or pregnancy status.
Specimen: Swab (sterile swab/transport medium, 1-2 swabs), Vaginal Swab (sterile swab/transport medium, 1-2 swabs), Rectal Swab (sterile swab/transport medium, 1-2 swabs). Transport in a biohazard container.
Sample Stability at Room Temperature: 2 hours
Sample Stability at Refrigeration: 24 hours
Sample Stability at Frozen: Not frozen
Medical History: Document fever, sepsis, or history of GBS infections, especially in pregnancy. Include current medications, especially antibiotics.
Consent: Written consent required, detailing the tests purpose, GBS infection implications, and risks of sample collection.
Procedural Considerations: Uses immunochromatographic assay to detect GBS antigens. Results are available in 1-2 days, supporting clinical decisions. Performed in laboratories, often for GBS diagnosis in pregnant women or newborns.
Factors Affecting Result Accuracy: Improper swab collection or delayed transport can affect results. Antibiotic use may reduce sensitivity.
Clinical Significance: Positive GBS antigens confirm infection, guiding antibiotic prophylaxis or therapy. Negative results may require culture or PCR.
Specialist Consultation: Consult an infectious disease specialist or obstetrician for result interpretation and treatment planning.
Additional Supporting Tests: GBS culture, PCR, or clinical evaluation to confirm GBS infection diagnosis.
Test Limitations: Sensitivity depends on sample quality; clinical correlation is needed. False negatives may occur.
References: ACOG GBS Guidelines, 2023; Clinical Infectious Diseases, Verani JR, 2022.
