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One-Step Strep B Rapid Test Cassette
Cat. No.: RH0508I
The Strep B Rapid Test Device (Swab) is a rapid visual immunoassay for the qualitative, presumptive detection of Group B Streptococcus (GBS) antigens in specimens taken from vaginal or rectal swaps of pregnant women , or general swabs from newborn. This kit is intended for use as an aid in the diagnosis of Strep B infection.
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.1 Several recent studies have shown that the intrapartum treatment of GBS-colonized women significantly reduces the incidence of GBS-caused sepsis. 2-4 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.
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.
Individually packed test devices
Each test contains colored conjugates and reactive reagents precoated at the corresponding regions.
| Reagent A||
|Reagent B||0.4 M acetic acid|
For specimen collection
|For adding specimens|
For specimen preparation
|For operating instructions|
Materials Required But Not Provided
STORAGE AND STABILITY
SPECIMEN COLLECTION AND PREPARATION
DIRECTIONS FOR USE
Bring tests, specimens, reagents and/or controls to room temperature (15-30°C) before use.
2. Remove the test from its sealed pouch, and place it on a clean, level surface. Label the device with patient or control identification. For best results, the assay should be performed within one hour.
3. Add 3 drops (approximately 120 μL) of extracted solution from the extraction tube to the sample well on the test device.
Avoid trapping air bubbles in the specimen well (S), and do not add any solution to the observation window.
As the test begins to work, color will migrate across the membrane.
INTERPRETATION OF RESULTS (Please refer to the illustration above)
POSITIVE: Two colored bands appear on the membrane. One band appears in the control region (C) and another band appears in the test region (T).
NEGATIVE: Only one colored band appears, in the control region (C). No apparent colored band appears in the test region (T).
INVALID: Control band fails to appear. Results from any test which has not produced a control band at the specified read time must be discarded. Please review the procedure and repeat with a new test. If the problem persists, discontinue using the kit immediately and contact your local distributor.
1. The intensity of color in the test region (T) may vary depending on the concentration of analytes present in the specimen. Therefore, any shade of color in the test region should be considered positive. Note that this is a qualitative test only, and cannot determine the concentration of analytes in the specimen.
2. Insufficient specimen volume, incorrect operating procedure or expired tests are the most likely reasons for control band failure.
internal positive procedural control. It confirms sufficient specimen volume and correct procedural technique.
Operating Procedure for External Quality Control Testing
Add 2-3 drops of the positive control directly into the specimen well of the test. Interpret results at 10 minutes. Do not interpret the result after 15 minutes.
Sensitivity and Specificity
The sensitivity (limit of detection) value of the test is 5.0×105 CFU (Colony Forming Units) per ml, or 2.5 x 104 CFU/test based on the 50 μl test sample. Positive results are obtained when the amount of GBS antigen in the test corresponds to this value or above. Conversely, negative results are obtained when the amount of the antigen is below the sensitivity of the test.
Relative Sensitivity: 90.48% Relative Specificity: 97.5% Overall Agreement : 95.08%
Table: Strep B Rapid Test vs. Culture
1. Finch, R.G., French, G.L., and Phillips, I.; Group B streptococci in the female genital tract; Br. Med. J., 1 (6020) 1245-1247, 1976
2. You, M.D., Mason, E.O., Leeds, L.J., Thompson, P.K., Clark, D.J. and Gardner, S.E.; Ampicilin prevents intrapartum transmission of group B streptococcus; JAMA 241 (12) 1245-1247 ,1979
3. Boyer, K.M., and Gotoff, S.P.; Prevention of early-onset neonatal group B streptococcal disease with selective intrapartum chemotaxis; N. Eng. J. Med. 314 1665-1669, 1986
4. Lim, D.V., Morales, W.J., Walsh, W.J. and Kazanis, D.; Reduction of morbidity and mortility rates for neonatal group B streptococcal disease through early diagnosis and chemoprophylaxis; J. Clin. Microbiol. 23 489-492, 1986
Span Biotech Ltd. is a research based company for rapid tests, with strong support from National Key Laboratory of Technology Projects of 10th and 11th Five-Year Plan and Faculty of Life Sciences of HuBei University. SpanBio also housed a R&D team that is developing gene recombination, cell cultivation and protein purification techniques. SpanBio pays strict attention on rapid tests for human being, animal diseases and food safety detection. It provides a number of customized services to professional distributors and partnering affiliates with excellent quality, competitive prices and super service.
Contact Person: Ms. Anna Lee